CN218352503U

CN218352503U - Optical module

Info

Publication number: CN218352503U
Application number: CN202222771414.7U
Authority: CN
Inventors: 张加傲; 王欣南; 慕建伟
Original assignee: Hisense Broadband Multimedia Technology Co Ltd
Current assignee: Hisense Broadband Multimedia Technology Co Ltd
Priority date: 2022-10-20
Filing date: 2022-10-20
Publication date: 2023-01-20
Anticipated expiration: 2032-10-20

Abstract

The optical module comprises a circuit board and an optical emitting device, wherein a DC-DC chip and a bias circuit are arranged on the surface of the circuit board, the optical emitting device comprises a laser, the laser comprises an electric absorption modulation area, the DC-DC chip provides reverse bias voltage for the electric absorption modulation area through the bias circuit, and meanwhile, a DSP chip provides a modulation signal for the electric absorption modulation area; the electro-absorption modulation region modulates light under a modulation signal and a reverse bias voltage. The bias circuit comprises a first unit and a second unit, wherein the first unit comprises a first magnetic bead and a second magnetic bead; the second unit includes an inductance and a resistance. When the optical module is in multiple channels, the first units and the second units in some channels can be electrically connected through routing on the surface of the circuit board, and the first units and the second units in other channels can be electrically connected through via holes between the surface of the circuit board and the middle layer, so that mutual crosstalk among the channels is avoided, reasonable layout is realized, and the performance of the optical module is improved.

Description

Optical module

Technical Field

The application relates to the technical field of optical communication, in particular to an optical module.

Background

The optical module includes a light emitting device and a light receiving device as photoelectric conversion devices. The light emitting device includes a laser, which is classified into a direct modulation laser and an external modulation laser according to a modulation method. An electro-absorption modulated laser (EML laser) is included in the external modulated laser.

The EML laser comprises a light emitting area and an electro-absorption modulation area, and bias current is supplied to the light emitting area, so that the light emitting area emits light without carrying information under the action of the bias current; the electric absorption modulation region is provided with reverse bias voltage, so that the electric absorption modulation region performs signal modulation on light emitted by the light emitting region under the action of the reverse bias voltage, and an optical signal carrying data is obtained. Specifically, the electro-absorption modulation regions have different absorption coefficients for light emitted by the light emitting region under the action of different reverse bias voltages, so that the light passes through or is absorbed by the electro-absorption modulation regions, information is loaded on the light emitted by the light emitting region, and the light is modulated.

Usually, a bias circuit provides a reverse bias voltage to the electro-absorption modulation region, and for the multi-channel optical module, different layout forms of the bias circuit may cause different influences, such as different parasitic capacitances generated by the different layout forms.

SUMMERY OF THE UTILITY MODEL

The application provides an optical module, and provides a bias circuit for a multi-channel optical module.

The application provides an optical module, includes:

the surface of the circuit board is provided with a DC-DC chip;

the light emitting device is electrically connected with the circuit board, comprises a laser and is used for converting an electric signal into an optical signal;

the laser, including:

a light emitting region for emitting light not carrying data;

the electroabsorption modulation region is used for modulating the light emitted by the light emitting region;

the DSP chip is electrically connected with the electroabsorption modulation area through a differential signal line and is used for providing a modulation signal for the electroabsorption modulation area;

the bias circuit is arranged on the circuit board, one end of the bias circuit is electrically connected with the DC-DC chip, the other end of the bias circuit is electrically connected with the electroabsorption modulation region, and the bias circuit comprises a first unit and a second unit which are connected in series and is used for providing negative bias voltage for the electroabsorption modulation region;

the first unit and the second unit are connected through a routing of the top layer of the circuit board or a via hole of the circuit board;

the first unit comprises a first magnetic bead and a second magnetic bead, and is electrically connected with the electroabsorption modulation region through the differential signal line;

the second unit comprises an inductor and a resistor and is electrically connected with the DC-DC chip.

The optical module comprises a circuit board and a light emitting device, wherein a DC-DC chip and a bias circuit are arranged on the surface of the circuit board, the light emitting device comprises a laser, the laser comprises a light emitting area and an electric absorption modulation area, one end of the bias circuit is electrically connected with the DC-DC chip, the other end of the bias circuit is electrically connected with the electric absorption modulation area, so that the DC-DC chip provides reverse bias voltage for the electric absorption modulation area through the bias circuit, and meanwhile, the DSP chip is electrically connected with the electric absorption modulation area through a differential signal line, so that the DSP chip provides a modulation signal for the electric absorption modulation area; the electro-absorption modulation region modulates the light emitted by the light emitting region under the action of the modulation signal and the reverse bias voltage to obtain an optical signal carrying information. Further, the bias circuit comprises a first unit and a second unit which are connected in series, the first unit comprises a first magnetic bead and a second magnetic bead, the first magnetic bead is connected with the differential signal line, and one end of the bias circuit is electrically connected with the electroabsorption modulation region through the differential signal line; the second unit comprises an inductor and a resistor, and is electrically connected with the DC-DC chip so as to realize that the other end of the bias circuit is electrically connected with the DC-DC chip. Because the modulation signal output by the DSP chip is an alternating current signal, the negative bias voltage output by the DC-DC chip is a direct current signal, and the modulation signal is transmitted to the electroabsorption modulation area through the same differential signal line, the first unit and the second unit in the bias circuit are used for allowing the negative bias voltage output by the DC-DC chip to pass and blocking the modulation signal output by the DSP chip from passing, thereby preventing the modulation signal output by the DSP chip from being transmitted to the DC-DC chip, and the first unit and the second unit in the bias circuit are used for passing the direct current negative bias voltage and blocking the alternating current modulation signal; when the optical module is a multi-channel optical module, the first units and the second units in some channels can be electrically connected through routing on the surface of the circuit board, and the first units and the second units in other channels can be electrically connected through via holes between the surface of the circuit board and the middle layer, so that mutual crosstalk among the channels is avoided, the generated parasitic capacitance is reduced, the bias circuits of the channels are reasonably distributed, and the performance of the optical module is improved.

Drawings

In order to more clearly illustrate the technical solutions in the present disclosure, the drawings needed to be used in some embodiments of the present disclosure will be briefly described below, and it is apparent that the drawings in the following description are only drawings of some embodiments of the present disclosure, and other drawings can be obtained by those skilled in the art according to the drawings. Furthermore, the drawings in the following description may be regarded as schematic diagrams, and do not limit the actual size of products, the actual flow of methods, the actual timing of signals, and the like, involved in the embodiments of the present disclosure.

FIG. 1 is a connection diagram of an optical communication system according to some embodiments;

FIG. 2 is a block diagram of an optical network terminal according to some embodiments;

FIG. 3 is a block diagram of a light module according to some embodiments;

FIG. 4 is an exploded view of a light module according to some embodiments;

FIG. 5 is a schematic diagram of bias circuit arrangements on a surface of a circuit board of an optical module according to some embodiments;

FIG. 6 is a schematic diagram of bias circuit settings on a circuit board surface of an optical module according to some embodiments;

FIG. 7 is a schematic diagram of bias circuit settings on a surface of a circuit board of an optical module according to some embodiments;

FIG. 8 is a schematic diagram of bias circuit settings on a circuit board surface of an optical module according to some embodiments;

FIG. 9 is a schematic diagram of bias circuit settings on a circuit board surface of an optical module according to some embodiments;

FIG. 10 is a schematic diagram of bias circuit arrangements on a circuit board surface of an optical module according to some embodiments;

fig. 11 is a schematic diagram of a circuit board surface bias circuit arrangement of an optical module according to some embodiments.

Detailed Description

In an optical communication system, an optical signal is used to carry information to be transmitted, and the optical signal carrying the information is transmitted to information processing equipment such as a computer through information transmission equipment such as an optical fiber or an optical waveguide, so as to complete information transmission. Since light has a passive transmission characteristic when transmitted through an optical fiber or an optical waveguide, low-cost, low-loss information transmission can be realized. Further, since a signal transmitted by an information transmission device such as an optical fiber or an optical waveguide is an optical signal and a signal that can be recognized and processed by an information processing device such as a computer is an electrical signal, it is necessary to perform interconversion between the electrical signal and the optical signal in order to establish an information connection between the information transmission device such as an optical fiber or an optical waveguide and the information processing device such as a computer.

The optical module realizes the function of interconversion between the optical signal and the electrical signal in the technical field of optical communication. The optical module comprises an optical port and an electric port, the optical module realizes optical communication with information transmission equipment such as optical fibers or optical waveguides and the like through the optical port, realizes electric connection with an optical network terminal (such as an optical modem) through the electric port, and the electric connection is mainly used for power supply, I2C signal transmission, data information transmission, grounding and the like; the optical network terminal transmits the electric signal to the computer and other information processing equipment through a network cable or a wireless fidelity (Wi-Fi).

Fig. 1 is a connection diagram of an optical communication system. As shown in fig. 1, the optical communication system includes a remote server 1000, a local information processing device 2000, an optical network terminal 100, an optical module 200, an optical fiber 101, and a network cable 103.

One end of the optical fiber 101 is connected to the remote server 1000, and the other end is connected to the optical network terminal 100 through the optical module 200. The optical fiber itself can support long-distance signal transmission, for example, signal transmission of thousands of meters (6 km to 8 km), on the basis of which if a repeater is used, theoretically infinite distance transmission can be realized. Therefore, in a typical optical communication system, the distance between the remote server 1000 and the optical network terminal 100 may be several kilometers, tens of kilometers, or hundreds of kilometers.

One end of the network cable 103 is connected to the local information processing device 2000, and the other end is connected to the optical network terminal 100. The local information processing apparatus 2000 may be any one or several of the following apparatuses: router, switch, computer, cell-phone, panel computer, TV set etc..

The physical distance between the remote server 1000 and the optical network terminal 100 is greater than the physical distance between the local information processing apparatus 2000 and the optical network terminal 100. The connection between the local information processing apparatus 2000 and the remote server 1000 is made by the optical fiber 101 and the network cable 103; and the connection between the optical fiber 101 and the network cable 103 is completed by the optical module 200 and the optical network terminal 100.

The optical module 200 includes an optical port configured to access the optical fiber 101, and an electrical port, such that the optical module 200 establishes a bidirectional optical signal connection with the optical fiber 101; the electrical port is configured to be accessed into the optical network terminal 100, so that the optical module 200 establishes a bidirectional electrical signal connection with the optical network terminal 100. The optical module 200 converts an optical signal and an electrical signal to each other, so that an information connection is established between the optical fiber 101 and the optical network terminal 100. For example, an optical signal from the optical fiber 101 is converted into an electrical signal by the optical module 200 and then input to the optical network terminal 100, and an electrical signal from the optical network terminal 100 is converted into an optical signal by the optical module 200 and input to the optical fiber 101. Since the optical module 200 is a tool for implementing the interconversion between the optical signal and the electrical signal, and has no function of processing data, information is not changed in the above-mentioned photoelectric conversion process.

The optical network terminal 100 includes a housing (housing) having a substantially rectangular parallelepiped shape, and an optical module interface 102 and a network cable interface 104 provided on the housing. The optical module interface 102 is configured to access the optical module 200, so that the optical network terminal 100 establishes a bidirectional electrical signal connection with the optical module 200; the network cable interface 104 is configured to access the network cable 103 such that the optical network terminal 100 establishes a bi-directional electrical signal connection with the network cable 103. The optical module 200 is connected to the network cable 103 via the optical network terminal 100. For example, the optical network terminal 100 transmits the electrical signal from the optical module 200 to the network cable 103, and transmits the electrical signal from the network cable 103 to the optical module 200, so that the optical network terminal 100 can monitor the operation of the optical module 200 as an upper computer of the optical module 200. The upper computer of the Optical module 200 may include an Optical Line Terminal (OLT) in addition to the Optical network Terminal 100.

The remote server 1000 establishes a bidirectional signal transmission channel with the local information processing device 2000 through the optical fiber 101, the optical module 200, the optical network terminal 100, and the network cable 103.

Fig. 2 is a structural diagram of the optical network terminal, and fig. 2 only shows a structure of the optical module 200 of the optical network terminal 100 in order to clearly show a connection relationship between the optical module 200 and the optical network terminal 100. As shown in fig. 2, the optical network terminal 100 further includes a circuit board 300 disposed within the housing, a cage 106 disposed on a surface of the circuit board 300, a heat sink 107 disposed on the cage 106, and an electrical connector disposed inside the cage 106. The electrical connector is configured to access an electrical port of the optical module 200; the heat sink 107 has a projection such as a fin that increases a heat radiation area.

The optical module 200 is inserted into a cage 106 of the optical network terminal 100, the cage 106 holds the optical module 200, and heat generated by the optical module 200 is conducted to the cage 106 and then diffused by a heat sink 107. After the optical module 200 is inserted into the cage 106, the electrical port of the optical module 200 is connected to the electrical connector inside the cage 106, so that the optical module 200 is connected to the optical network terminal 100 by a bidirectional electrical signal. Further, the optical port of the optical module 200 is connected to the optical fiber 101, and the optical module 200 establishes bidirectional optical signal connection with the optical fiber 101.

Fig. 3, 4 are block diagrams of a light module according to some embodiments. As shown in fig. 3 and 4, the optical module 200 includes a housing (shell), a circuit board 300 disposed in the housing, and an optical transceiver module.

The shell comprises an upper shell 201 and a lower shell 202, wherein the upper shell 201 is covered on the lower shell 202 to form the shell with two openings; the outer contour of the housing generally appears square.

In some embodiments of the present disclosure, the lower housing 202 includes a bottom plate 2021 and two lower side plates 2022 located at both sides of the bottom plate 2021 and disposed perpendicular to the bottom plate 2021; the upper case 201 includes a cover 2011, and the cover 2011 covers the two lower side plates 2022 of the lower case 202 to form the above case.

In some embodiments, the lower housing 202 includes a bottom plate 2021 and two lower side plates 2022 located at both sides of the bottom plate 2021 and disposed perpendicular to the bottom plate 2021; the upper case 201 includes a cover plate 2011 and two upper side plates which are located on two sides of the cover plate 2011 and are perpendicular to the cover plate 2011, and the two upper side plates and the two lower side plates 2022 are combined to cover the upper case 201 on the lower case 202.

The direction of the connecting line of the two

openings

204 and 205 may be the same as the length direction of the optical module 200, or may not be the same as the length direction of the optical module 200. For example, the opening 204 is located at an end portion (right end in fig. 3) of the optical module 200, and the opening 205 is also located at an end portion (left end in fig. 3) of the optical module 200. Alternatively, the opening 204 is located at an end of the optical module 200, and the opening 205 is located at a side of the optical module 200. The opening 204 is an electrical port, and a gold finger of the circuit board 300 extends out of the opening 204 and is inserted into an upper computer (for example, the optical network terminal 100); the opening 205 is an optical port configured to access the external optical fiber 101, so that the external optical fiber 101 is connected to an optical transceiver module inside the optical module 200.

The upper shell 201 and the lower shell 202 are combined to facilitate the installation of devices such as the circuit board 300 and the optical transceiver module into the shell, and the upper shell 201 and the lower shell 202 form encapsulation protection for the devices. In addition, when the circuit board 300, the optical transceiver module and other devices are assembled, the positioning components, the heat dissipation components and the electromagnetic shielding components of the devices are convenient to arrange, and the automatic production is facilitated.

In some embodiments, the upper housing 201 and the lower housing 202 are generally made of a metal material, which is beneficial to achieve electromagnetic shielding and heat dissipation.

In some embodiments, the optical module 200 further includes an unlocking part 203 located outside the housing thereof, and the unlocking part 203 is configured to realize a fixed connection between the optical module 200 and the upper computer or release the fixed connection between the optical module 200 and the upper computer.

For example, the unlocking member 203 is located on the outer walls of the two lower side plates 2022 of the lower housing 202, and has a snap-fit member that matches with a cage of the upper computer (for example, the cage 106 of the optical network terminal 100). When the optical module 200 is inserted into the cage of the upper computer, the optical module 200 is fixed in the cage of the upper computer by the engaging member of the unlocking member; when the unlocking member is pulled, the engaging member of the unlocking member moves along with the unlocking member, and the connection relationship between the engaging member and the upper computer is changed, so that the engaging relationship between the optical module 200 and the upper computer is released, and the optical module 200 can be drawn out from the cage of the upper computer.

The circuit board 300 includes circuit traces, electronic components, and chips, and the electronic components and the chips are connected together by the circuit traces according to a circuit design to implement functions of power supply, electrical signal transmission, grounding, and the like. Examples of the electronic components include capacitors, resistors, transistors, and Metal-Oxide-Semiconductor Field-Effect transistors (MOSFETs). The chip includes, for example, a Micro Controller Unit (MCU), a laser driving chip, a limiting amplifier (limiting amplifier), a Clock and Data Recovery (CDR) chip, a power management chip, and a Digital Signal Processing (DSP) chip.

The circuit board 300 is generally a rigid circuit board, which can also perform a bearing function due to its relatively rigid material, for example, the rigid circuit board can stably bear the electronic components and chips; when the optical transceiver component is positioned on the circuit board, the rigid circuit board can also provide smooth bearing; the rigid circuit board can also be inserted into an electric connector in the cage of the upper computer.

The circuit board 300 further includes a gold finger formed on an end surface thereof, the gold finger being composed of a plurality of pins independent of each other. The circuit board 300 is inserted into the cage 106 and electrically connected to the electrical connector in the cage 106 by gold fingers. The gold fingers may be disposed on only one side of the circuit board 300 (e.g., the upper surface shown in fig. 4), or may be disposed on both upper and lower sides of the circuit board 300, so as to adapt to the situation where the requirement of the number of pins is large. The golden finger is configured to establish an electrical connection with the upper computer to realize power supply, grounding, I2C signal transmission, data signal transmission and the like.

Of course, a flexible circuit board is also used in some optical modules. Flexible circuit boards are generally used in conjunction with rigid circuit boards to supplement the rigid circuit boards. For example, a flexible circuit board may be used to connect the rigid circuit board and the optical transceiver module.

The optical transceiver module includes a light emitting device 400 and a light receiving device 500, the light emitting device 400 is configured to realize emission of an optical signal, and the light receiving device 500 is configured to realize reception of the optical signal. Illustratively, the light emitting device 400 and the light receiving device 500 are combined together to form an integrated light transceiving component.

The most critical structure in a light emitting device is a laser, including an EML laser. The EML laser includes a light emitting region and an electro-absorption modulation region. The light emitting area emits light without carrying data under the action of bias current, the electroabsorption modulation area modulates the light emitted by the light emitting area under the action of bias voltage, and further the electroabsorption modulation area modulates the light emitted by the light emitting area under the action of reverse bias voltage. Specifically, the electro-absorption modulator is a PIN semiconductor device, and is mainly composed of a P-type semiconductor, an N-type semiconductor, an absorption layer (composed of a multiple quantum well waveguide), and a metal layer. The absorption layer utilizes quantum Stark effect, and the absorption peak of the absorption layer can move under the action of an external bias voltage, so that for the light emitted by a light emitting region with a certain wavelength, the absorption capacity of the absorption layer on the light emitted by the light emitting region can be controlled by adjusting the bias voltage, and a changed voltage signal is modulated on the light emitted by the light emitting region to realize the intensity modulation of the light.

The embodiment of the application provides a bias circuit, which provides bias voltage for an electro-absorption modulation region through the bias circuit so as to realize light modulation. Specifically, the surface of the circuit board is provided with a DC-DC chip and a bias circuit, the light emitting device comprises a laser, the laser comprises an electro-absorption modulation region, the DC-DC chip provides reverse bias voltage for the electro-absorption modulation region through the bias circuit, and meanwhile, the DSP chip provides a modulation signal for the electro-absorption modulation region; the electro-absorption modulation region modulates light under a modulation signal and a reverse bias voltage. The bias circuit comprises a first unit and a second unit, wherein the first unit comprises a first magnetic bead and a second magnetic bead; the second unit includes an inductance and a resistance. When the optical module is a multi-channel optical module, the first units and the second units in some channels can be electrically connected through routing on the surface of the circuit board, and the first units and the second units in other channels can be electrically connected through the via holes between the surface of the circuit board and the middle layer, so that mutual crosstalk among the channels is avoided.

According to the working principle of the electro-absorption modulator, a reverse bias voltage needs to be provided for the electro-absorption modulation region, so that the normal work of the electro-absorption modulation region can be ensured. In the embodiment of the application, the negative voltage is provided for the anode of the electro-absorption modulation region through the DC-DC chip on the circuit board, and then the reverse bias voltage is provided for the electro-absorption modulation region.

In some embodiments of the present application, the DC-DC chip provides a reverse bias voltage to the electro-absorption modulation region through the bias circuit, and the reverse bias voltage of the DC-DC output is a direct current reverse bias voltage. The reverse bias voltage is a key parameter of EML lasers, which directly affects the absorption characteristics of the laser to light.

In some embodiments of the present application, the DSP chip provides a modulation signal to the electro-absorption modulation region through a differential signal line, and the modulation signal output by the DSP chip is an alternating current signal, specifically, the modulation signal output by the DSP chip is a differential signal, so that the DSP signal is transmitted by using the differential signal line; the DSP chip outputs a modulation signal of PAM4, with four levels in the PAM4 modulation signal to represent the modulated information. Further, the differential transmission line is a differential signal line pair and comprises two differential signal lines, in the embodiment of the application, one of the differential signal lines is electrically connected with the anode of the electro-absorption modulation area, and the cathode of the electro-absorption modulation area is grounded. In order to avoid that the signal on the other differential signal line returns to the DSP chip and causes crosstalk to the DSP output signal, in this embodiment of the application, the other differential signal line may be matched with the matching resistor, for example, a matching resistor of 50 Ω is adopted to be connected in parallel with the other differential signal line, so that the signal on the other differential signal line is absorbed by the resistor of 50 Ω, and is prevented from returning to the DSP chip.

The electroabsorption modulation area in the application has two input ends, namely a first input end and a second input end, wherein the first input end is used for inputting reverse bias voltage, and the second input end is used for inputting modulation signals; further, the bias circuit is electrically connected with the first input end, and the DSP chip is electrically connected with the second input end; the electroabsorption modulation region realizes the intensity modulation of the light emitted by the light emitting region under the combined action of the reverse bias voltage and the modulation signal.

In some embodiments of the present application, the bias circuit has one end electrically connected to the DC-DC chip and the other end electrically connected to the positive electrode of the electro-absorption modulation region; specifically, the other end of the bias circuit is also electrically connected with the anode of the electroabsorption modulation area through a differential signal line, because the signal transmitted by the bias voltage is a direct current signal, and the signal transmitted by the DSP chip is an alternating current signal, in order to avoid the signal output by the DSP chip being transmitted to the DC-DC chip through the differential signal line and causing interference to the DC-DC chip, the bias circuit further includes a first unit and a second unit which are connected in series with each other, the first unit includes a first magnetic bead and a second magnetic bead which are connected in series with each other, and the second unit includes an inductor and a resistor which are connected in parallel with each other. The first magnetic bead and the second magnetic bead which are connected in series are used for allowing the negative bias voltage output by the DC-DC chip to pass and blocking the modulation signal output by the DSP chip from passing, so that the modulation signal output by the DSP chip is prevented from being transmitted to the DC-DC chip, and therefore the first unit and the second unit in the bias circuit are used for connecting the direct current negative bias voltage and blocking the alternating current modulation signal; in order to completely block the modulation signal output by the DSP chip, the inductors and the resistors which are connected in parallel further block the modulation signal output by the DSP chip from passing through, so that the modulation signal output by the DSP chip is prevented from being transmitted to the DC-DC chip to a greater extent, and the normal work of the DC-DC chip is ensured. Meanwhile, the second unit can be used for filtering the negative voltage signal output by the DC-DC chip.

Because the negative voltage output by the DC-DC chip has certain fluctuation, a filter capacitor is connected in parallel to the bias circuit in the embodiment of the application and is used for filtering the negative voltage output by the DC-DC chip. Specifically, one end of the filter capacitor is electrically connected with the bias circuit, the other end of the filter capacitor is grounded, and the DC-DC chip electrically connected with one end of the bias circuit is grounded, so that the filter capacitor and the bias circuit are connected in parallel. The circuit board is a multilayer circuit board and comprises a top layer, a second layer, a third layer, a fourth layer and a fifth layer \8230, the bottom layer is provided with GND, the second layer is a ground layer, the GND of the top layer and the second layer can be electrically connected through a through hole, the filter capacitor can be connected to the GND of the top layer, and the DC-DC chip can be connected to the GND of the second layer.

When the optical module is a multichannel optical module, the optical module comprises a plurality of bias circuits, and how each bias circuit is arranged can directly influence the working performance of the optical module; mutual crosstalk among the bias circuits is avoided, parasitic capacitance is reduced, and reasonable layout is achieved.

As shown in fig. 5 and 6, when the optical module has eight channels, the DSP chip is connected to the first differential signal line, the second differential signal line, the third differential signal line, the fourth differential signal line, the fifth differential signal line, the sixth differential signal line, the seventh differential signal line, and the eighth differential signal line, respectively, and provides the modulation signal to the electro-absorption modulation region of the corresponding channel through the corresponding differential signal line, respectively. As is apparent from fig. 5, the first differential signal line, the second differential signal line, the third differential signal line, the fourth differential signal line, the fifth differential signal line, the sixth differential signal line, the seventh differential signal line, and the eighth differential signal line arranged from above and below are connected.

When the optical module is an eight-channel optical module, the surface of the circuit board is respectively provided with a first bias circuit, a second bias circuit, a third bias circuit, a fourth bias circuit, a fifth bias circuit, a sixth bias circuit, a seventh bias circuit and an eighth bias circuit, and bias voltages are respectively provided to the electro-absorption modulation regions of the corresponding channels through the corresponding bias circuits, and as is apparent from fig. 5, the bias circuits are arranged at different positions.

As shown in fig. 5 and fig. 6, in the embodiment of the present application, each bias circuit includes a corresponding first unit and a corresponding second unit, where the first unit includes a first magnetic bead and a second magnetic bead that are connected in series, and the first magnetic bead is electrically connected to a corresponding differential signal line; and the second unit is electrically connected with the DC-DC chip, one end of the bias circuit is electrically connected with the DC-DC chip, and the other end of the bias circuit is electrically connected with the anode of the electro-absorption modulation area through a corresponding differential signal line.

In the first channel, the DSP chip is connected with the electroabsorption modulation area through a first differential signal line so as to provide a modulation signal for the electroabsorption modulation area; the DC-DC chip provides a reverse bias voltage for the electro-absorption modulation region through a first bias circuit; a first unit in the first bias circuit is electrically connected with a first differential signal line so as to be electrically connected with the positive electrode of the electro-absorption modulation area, and a second unit is arranged on one side of the first differential signal line and is electrically connected with the DC-DC chip; specifically, one end of a first magnetic bead in the first bias circuit is connected with the differential signal line, and the other end of the first magnetic bead is connected with a second magnetic bead, namely, the first magnetic bead and the second magnetic bead are connected in series; the inductor and the resistor are connected in parallel and then connected in series with the first unit. The surface of the circuit board is respectively provided with a first magnetic bead first bonding pad 311 and a first magnetic bead second bonding pad 312, which are used for arranging a first magnetic bead, specifically, one end of the first magnetic bead is arranged on the first magnetic bead first bonding pad 311, and the other end of the first magnetic bead is arranged on the first magnetic bead second bonding pad 312; the surface of the circuit board is respectively provided with a first pad 313 of a second magnetic bead and a second pad 314 of the second magnetic bead for setting the second magnetic bead, specifically, one end of the second magnetic bead is arranged on the first pad 313 of the second magnetic bead, and the other end of the second magnetic bead is arranged on the second pad 314 of the second magnetic bead. The first magnetic bead first bonding pad 311 and the first magnetic bead second bonding pad 312 are vertically arranged, and then the first magnetic bead is vertically arranged; the second magnetic bead first bonding pad 313 and the second magnetic bead second bonding pad 314 are horizontally arranged, and the side second magnetic beads are horizontally arranged; the first magnetic bead second bonding pad 312 is connected to the second magnetic bead first bonding pad 313 to realize the series connection of the first magnetic bead and the second magnetic bead. An inductor first bonding pad 315 and an inductor second bonding pad 316 are respectively arranged on the surface of the circuit board and used for arranging an inductor, specifically, one end of the inductor is arranged on the inductor first bonding pad 315, and the other end of the inductor is arranged on the inductor second bonding pad 316; the surface of the circuit board is provided with a first resistor pad 317 and a second resistor pad 318, respectively, for providing a resistor, specifically, one end of the resistor is provided on the first resistor pad 317, and the other end is provided on the second resistor pad 318. The inductor first pad 315 is connected to the resistor first pad 317 and the inductor second pad 316 is connected to the resistor second pad 318 to achieve a parallel connection of the inductor and the resistor.

The second magnetic bead second pad 314 is connected to the inductor first pad 315 to realize a series connection of the first cell and the second cell.

One end of the second inductor pad 316 is connected to the second resistor pad 318, the other end of the second inductor pad is connected to the first filter capacitor pad 319, the first filter capacitor pad 319 is used for setting one end of the filter capacitor, and the other end of the filter capacitor is grounded and connected to the second inductor pad 316 through the first filter capacitor pad 319, so that the parallel connection of the filter capacitor and the bias circuit is realized.

Therefore, in the first channel, the first unit and the second unit are both provided with circuit board top layers, and the first unit and the second unit are connected through routing of the circuit board top layers.

In the second channel, the DSP chip is electrically connected with the anode of the electroabsorption modulation area through a second differential signal line so as to provide a modulation signal for the electroabsorption modulation area; the DC-DC chip provides a reverse bias voltage for the electro-absorption modulation region through a second bias circuit; the first unit in the second bias circuit is electrically connected with the second differential signal line so as to be electrically connected with the anode of the electroabsorption modulation area, and the second unit is arranged on one side of the first differential signal line and is electrically connected with the DC-DC chip; specifically, a first unit in the second bias circuit is arranged between a first differential signal line and a second differential signal line, a first magnetic bead of the first unit is electrically connected with the second differential signal line, and a second unit is arranged on one side of the first differential signal line and is adjacent to a second unit in the first bias circuit. Specifically, the surface of the circuit board is provided with corresponding pads of each structure of the second bias circuit, the surface of the circuit board is provided with a first pad 321 of a first magnetic bead, a second pad 322 of the first magnetic bead, a first pad 323 of the second magnetic bead, and a second pad 324 of the second magnetic bead, the setting relationship and the connection relationship of the first pad 321 of the first magnetic bead, the second pad 322 of the first magnetic bead, the first pad 323 of the second magnetic bead, and the second pad 324 of the second magnetic bead are the same as those of the first bias circuit, and the difference is that: the second magnetic bead second bonding pad 314 of the first bias circuit is connected with the inductor first bonding pad 315, and the second magnetic bead second bonding pad 324 of the second bias circuit board is not connected with the inductor first bonding pad 325. Similarly, the surface of the circuit board is further provided with an inductor first bonding pad 325, an inductor second bonding pad 326, a resistor first bonding pad 327 and a resistor second bonding pad 328, respectively, which are arranged in the same relationship as the first bias circuit, so as to realize parallel connection of the inductor and the resistor. The second unit of the second bias circuit is arranged at the adjacent position of the first unit of the first bias circuit, that is, the first unit and the second unit in the second bias circuit are not arranged together but are arranged separately, in order to avoid mutual crosstalk, the first unit and the second unit in the second bias circuit are connected through a circuit board via hole, specifically, a via hole is arranged from the top layer of the circuit board to the third layer of the circuit board, and then the first unit and the second unit in the second bias circuit are electrically connected through the via hole; because the second layer is a grounding layer, the via holes are arranged from the top layer of the circuit board to the third layer of the circuit board according to the length of the routing, the depth of the via holes and other factors, the routing length and the depth of the via holes can be shortened, and the parasitic capacitance caused by the routing and the via holes is reduced.

In the third channel, the DSP chip is electrically connected with the anode of the electroabsorption modulation area through a third differential signal line so as to provide a modulation signal for the electroabsorption modulation area; the DC-DC chip provides a reverse bias voltage for the electro-absorption modulation region through a third bias circuit; the first unit in the third bias circuit is electrically connected with the third differential signal line so as to be electrically connected with the anode of the electroabsorption modulation area, and the second unit is arranged on one side of the first differential signal line and is electrically connected with the DC-DC chip; specifically, the first unit in the third bias circuit is arranged between the second differential signal line and the third differential signal line, and the second unit is arranged on one side of the first differential signal line, specifically at the adjacent position of the second unit of the second bias circuit; the surface of the circuit board is provided with corresponding bonding pads of structures of a second bias circuit, the surface of the circuit board is provided with a first magnetic bead first bonding pad 331, a first magnetic bead second bonding pad 332, a second magnetic bead first bonding pad 333 and a second magnetic bead second bonding pad 334, and the arrangement relation and the connection relation of the first magnetic bead first bonding pad 331, the first magnetic bead second bonding pad 332, the second magnetic bead first bonding pad 333 and the second magnetic bead second bonding pad 334 are the same as those in the second bias circuit; the circuit board is further provided with an inductor first bonding pad 335, an inductor second bonding pad 336, a resistor first bonding pad 337 and a resistor second bonding pad 338 respectively, which are arranged in the same relationship as the aforementioned second bias circuit, so as to realize the parallel connection of the inductor and the resistor, and the second magnetic bead second bonding pad 334 is not connected with the inductor first bonding pad 335; the second unit of the third bias circuit is disposed adjacent to the second unit of the second bias circuit, that is, the first unit and the second unit in the third bias circuit are not disposed together but disposed separately, in order to avoid mutual crosstalk, the first unit and the second unit in the third bias circuit are connected through a via hole of a circuit board, specifically, a via hole is disposed from a top layer of the circuit board to a third layer of the circuit board, and then the first unit and the second unit in the third bias circuit are electrically connected through the via hole.

In the fourth channel, the DSP chip is electrically connected with the anode of the electroabsorption modulation area through a fourth differential signal line so as to provide a modulation signal for the electroabsorption modulation area; the DC-DC chip provides a reverse bias voltage for the electro-absorption modulation region through a fourth bias circuit; a first unit in the fourth bias circuit is arranged between the third differential signal line and the fourth differential signal line, is electrically connected with the fourth differential signal line so as to be electrically connected with the anode of the electro-absorption modulation area, and a second unit is arranged between the fourth differential signal line and the fifth differential signal line and is electrically connected with the DC-DC chip; specifically, the surface of the circuit board is provided with corresponding pads of each structure of the second bias circuit, and the surface of the circuit board is provided with the same arrangement relationship and connection relationship of the first magnetic bead first pad 341, the first magnetic bead second pad 342, the second magnetic bead first pad 343 and the second magnetic bead second pad 344 as those of the second bias circuit or the third bias circuit; the surface of the circuit board is further provided with an inductor first pad 345, an inductor second pad 346, a resistor first pad 347 and a resistor second pad 348, the second bias circuit or the third bias circuit is arranged in a relationship as described above, the parallel connection of the inductor and the resistor is realized, and the second magnetic bead second pad 344 is not connected with the inductor first pad 345; the first unit and the second unit in the fourth bias circuit are not arranged together, but are arranged separately, in order to avoid mutual crosstalk, the first unit and the second unit in the fourth bias circuit are connected through a circuit board via hole, specifically, a via hole is arranged from the top layer of the circuit board to the third layer of the circuit board, and then the first unit and the second unit in the fourth bias circuit are electrically connected through the via hole.

In the fifth channel, the DSP chip is electrically connected with the anode of the electroabsorption modulation area through a fifth differential signal line so as to provide a modulation signal for the electroabsorption modulation area; the DC-DC chip provides a reverse bias voltage for the electro-absorption modulation region through a fifth bias circuit; a first unit in the fifth bias circuit is electrically connected with a fifth differential signal line so as to be electrically connected with the anode of the electro-absorption modulation area, and a second unit is arranged between the fourth differential signal line and the fifth differential signal line and is electrically connected with the DC-DC chip; specifically, a first magnetic bead first bonding pad 351, a first magnetic bead second bonding pad 352, a second magnetic bead first bonding pad 353, a second magnetic bead second bonding pad 354, an inductor first bonding pad 355, an inductor second bonding pad 356, a resistor first bonding pad 357 and a resistor second bonding pad 358 are respectively arranged on the surface of the circuit board; the connection relationship between the pads is the same as the first bias circuit, and the first magnetic bead second pad 352 and the second magnetic bead first pad 353 are connected to realize the series connection of the first magnetic bead and the second magnetic bead; the second magnetic bead second bonding pad 354 and the inductance first bonding pad 355 are directly connected, and the connection is realized through wiring on the top layer of the circuit board, so that the first unit and the second unit are connected in series; the arrangement positions of the first unit and the second unit in the fifth bias circuit are the same as the arrangement positions of the first unit and the second unit in the first bias circuit, and the first unit and the second unit in the fifth bias circuit are not separately arranged but are intensively arranged between the fourth differential signal line and the fifth differential signal line; the first unit and the second unit in the fifth bias circuit are connected through the top-layer routing of the circuit board, that is, the second magnetic bead second pad is connected with the inductor first pad, so as to realize the series connection of the first unit and the second unit.

In the sixth channel, the DSP chip is electrically connected with the anode of the electroabsorption modulation area through a sixth differential signal line so as to provide a modulation signal for the electroabsorption modulation area; the DC-DC chip provides a reverse bias voltage for the electro-absorption modulation region through a sixth bias circuit; the first unit in the sixth bias circuit is electrically connected with the sixth differential signal line so as to be electrically connected with the anode of the electroabsorption modulation area, and the second unit is arranged on one side of the eighth differential signal line and is electrically connected with the DC-DC chip; specifically, a first magnetic bead first bonding pad 361, a first magnetic bead second bonding pad 362, a second magnetic bead first bonding pad 363, a second magnetic bead second bonding pad 364, an inductor first bonding pad 365, an inductor second bonding pad 366, a resistor first bonding pad 367 and a resistor second bonding pad 368 are respectively arranged on the surface of the circuit board; the first magnetic bead first pad 361, the first magnetic bead second pad 362, the second magnetic bead first pad 363, and the second magnetic bead second pad 364 are arranged in the same manner as the bias circuit, and the first magnetic bead second pad 362 and the second magnetic bead first pad 363 are connected to realize the serial connection of the first magnetic bead and the second magnetic bead; the second magnetic bead second bonding pad 364 and the inductance first bonding pad 365 are not connected and are connected through via holes; the arrangement relationship of the inductor first bonding pad 365, the inductor second bonding pad 366, the resistor first bonding pad 367 and the resistor second bonding pad 368 is the same as that of the bias circuit, so that the parallel connection of the inductor and the resistor is realized; the first unit in the sixth bias circuit is arranged between the fifth differential signal line and the sixth differential signal line and is electrically connected with the fifth differential signal line, the second unit is arranged separately from the first unit, and the second unit is arranged on one side of the eighth differential signal line. Specifically, the surface of the circuit board is provided with corresponding pads of each structure of the sixth bias circuit, and the surface of the circuit board is provided with a first magnetic bead pad, a second magnetic bead pad, a first magnetic bead pad, and a second magnetic bead pad, which are arranged in the same manner as the second bias circuit, the third bias circuit, or the fourth bias circuit, and connected to each other. The first unit and the second unit in the sixth bias circuit are not arranged together, but are arranged separately, in order to avoid mutual crosstalk, the first unit and the second unit in the sixth bias circuit are connected through a circuit board via hole, specifically, a via hole is arranged from the top layer of the circuit board to the third layer of the circuit board, and then the first unit and the second unit in the sixth bias circuit are electrically connected through the via hole.

In the seventh channel, the DSP chip is electrically connected with the anode of the electroabsorption modulation area through a seventh differential signal line so as to provide a modulation signal for the electroabsorption modulation area; the DC-DC chip provides a reverse bias voltage for the electro-absorption modulation region through a seventh bias circuit; the first unit in the seventh bias circuit is electrically connected with the seventh differential signal line so as to be electrically connected with the anode of the electroabsorption modulation area, and the second unit is arranged on one side of the eighth differential signal line and is electrically connected with the DC-DC chip; specifically, the surface of the circuit board is provided with a first magnetic bead first bonding pad 371, a first magnetic bead second bonding pad 372, a second magnetic bead first bonding pad 373, a second magnetic bead second bonding pad 374, an inductor first bonding pad 375, an inductor second bonding pad 376, a resistor first bonding pad 377 and a resistor second bonding pad 378 respectively; the first magnetic bead first pad 371, the first magnetic bead second pad 372, the second magnetic bead first pad 373, and the second magnetic bead second pad 374 are arranged in the same manner as the bias circuit, and the first magnetic bead second pad 372 and the second magnetic bead first pad 373 are connected to realize the serial connection of the first magnetic bead and the second magnetic bead; the second magnetic bead second bonding pad 374 and the inductance first bonding pad 375 are not connected and are connected through via holes; the inductor first bonding pad 375, the inductor second bonding pad 376, the resistor first bonding pad 377 and the resistor second bonding pad 378 are arranged in a manner similar to the bias circuit, so that the parallel connection of the inductor and the resistor is realized; the first unit in the seventh bias circuit is arranged between the sixth differential signal line and the seventh differential signal line and is electrically connected with the seventh differential signal line; the second unit is arranged adjacent to the second unit of the sixth bias circuit; specifically, the surface of the circuit board is provided with corresponding pads of each structure of the seventh bias circuit, and the surface of the circuit board is provided with a first magnetic bead pad, a second magnetic bead pad, a first magnetic bead pad, and a second magnetic bead pad, which are arranged in the same manner as the second bias circuit, the third bias circuit, the fourth bias circuit, or the sixth bias circuit, and which are connected in the same manner. The first unit and the second unit in the seventh bias circuit are not arranged together, but are arranged separately, in order to avoid mutual crosstalk, the first unit and the second unit in the seventh bias circuit are connected through a circuit board via hole, specifically, a via hole is arranged from the top layer of the circuit board to the third layer of the circuit board, and then the first unit and the second unit in the seventh bias circuit are electrically connected through the via hole.

In the eighth channel, the DSP chip is electrically connected with the anode of the electroabsorption modulation area through an eighth differential signal line so as to provide a modulation signal for the electroabsorption modulation area; the DC-DC chip provides a reverse bias voltage for the electro-absorption modulation region through an eighth bias circuit; the first unit in the eighth bias circuit is electrically connected with the eighth differential signal line so as to be electrically connected with the anode of the electroabsorption modulation area, and the second unit is arranged on one side of the eighth differential signal line and is electrically connected with the DC-DC chip; specifically, the surface of the circuit board is provided with a first magnetic bead first pad 381, a first magnetic bead second pad 382, a second magnetic bead first pad 383, a second magnetic bead second pad 384, an inductance first pad 385, an inductance second pad 386, a resistance first pad 387, and a resistance second pad 388; the first magnetic bead first pad 381, the first magnetic bead second pad 382, the second magnetic bead first pad 383, and the second magnetic bead second pad 384 are arranged in the same manner as the bias circuit, and the first magnetic bead second pad 382 and the second magnetic bead first pad 383 are connected to realize the series connection of the first magnetic bead and the second magnetic bead; the second magnetic bead second bonding pad 384 and the inductance first bonding pad 385 are not connected and are connected through a through hole; the inductor first bonding pad 385, the inductor second bonding pad 386, the resistor first bonding pad 387 and the resistor second bonding pad 388 are arranged in a manner similar to the bias circuit, so that the parallel connection of the inductor and the resistor is realized; the first unit in the eighth bias circuit is arranged between the seventh differential signal line and the eighth differential signal line and is connected with the seventh differential signal line; the second unit is arranged at the adjacent position of the second unit of the seventh channel; specifically, the surface of the circuit board is provided with corresponding pads of each structure of the seventh bias circuit, and the surface of the circuit board is provided with the arrangement relationship and the connection relationship of the first magnetic bead pad, the first magnetic bead second pad, the second magnetic bead first pad and the second magnetic bead second pad, which are the same as those of the second bias circuit, the third bias circuit, the fourth bias circuit, the sixth bias circuit or the seventh bias circuit. The first unit and the second unit in the eighth bias circuit are not arranged together, but are arranged separately, in order to avoid mutual crosstalk, the first unit and the second unit in the eighth bias circuit are connected through a circuit board via hole, specifically, a via hole is arranged from the top layer of the circuit board to the third layer of the circuit board, and then the first unit and the second unit in the eighth bias circuit are electrically connected through the via hole.

As can be seen from the above description of the arrangement of the bias circuits of the channels of the optical module, in the embodiment of the present application, the bias circuits of the channels include a first unit and a second unit, and in order to arrange a plurality of bias circuits on a limited circuit board space, the second unit and the second unit in the bias circuits may be collectively arranged at the same position or may be separately arranged; when the first unit and the second unit in the bias circuit are intensively arranged at the same position, the first unit and the second unit can be directly electrically connected through the routing of the top layer of the circuit board, such as a first bias circuit and a fifth bias circuit; when the first unit and the second unit in the bias circuit are not arranged together but are arranged separately, the first unit and the second unit are electrically connected through a circuit board through hole; therefore, the bias circuits are compactly and reasonably arranged on the circuit board, mutual crosstalk among the bias circuits is avoided, the generated parasitic capacitance is reduced, and the normal work of the bias circuits of the optical module is ensured.

In each channel, the circuit board is provided with a filter capacitor in parallel at the corresponding bias circuit position, and in order to set the corresponding filter capacitor, the circuit board is provided with a first filter capacitor pad, a second filter capacitor pad, a third filter capacitor pad, a fourth filter capacitor pad, a fifth filter capacitor pad, a sixth filter capacitor pad, a seventh filter capacitor pad and an eighth filter capacitor pad respectively. As shown in fig. 8, the first filter capacitor pad is connected to the second pad of the inductor in the first bias circuit such that the corresponding filter capacitor is connected in parallel to the first bias circuit; the second filter capacitor bonding pad is arranged at a connecting bonding pad between the first inductance bonding pad and the first resistance bonding pad in the second bias circuit, and the second filter capacitor bonding pad is connected with the first inductance bonding pad or the first resistance bonding pad in the second bias circuit so as to enable the corresponding filter capacitor to be connected with the second bias circuit in parallel; the third filter capacitor bonding pad is arranged in the same manner as the second filter capacitor bonding pad; the fourth filter capacitor bonding pad and the first filter capacitor bonding pad are arranged in the same mode; the respective arrangement modes of the fifth filter capacitor bonding pad, the sixth filter capacitor bonding pad, the seventh filter capacitor bonding pad and the eighth filter capacitor bonding pad are the same as the arrangement mode of the second filter capacitor bonding pad.

When the optical module is 16 channels, 16 corresponding bias circuits are arranged on the circuit board to provide reverse bias voltage. The setting relationship among the 16 bias circuits is shown in fig. 7-11; FIG. 7 is an overall schematic diagram of a 16-channel bias circuit; FIG. 8 is a schematic diagram of a structure of an 8-channel bias circuit, and FIG. 9 is a partial schematic diagram of FIG. 8; fig. 10 is a schematic diagram of another 8-channel bias circuit, and fig. 11 is a partial schematic diagram of fig. 10.

As shown in fig. 7, in order to realize the function of the 16-channel bias circuit, an eight-channel bias circuit, namely a first bias circuit, a second bias circuit, 8230and an eighth bias circuit, is arranged at the first end of the circuit board; the second end is provided with an eight-channel bias circuit which is a ninth bias circuit, a tenth bias circuit, a 8230and a sixteenth bias circuit respectively; a first DSP chip 630, a first DC-DC chip 610, a second DSP chip 640 and a second DC-DC chip 620 are respectively arranged in the middle, the first DSP chip 630 is arranged close to an eight-channel bias circuit at a first end, and the second DSP chip 640 is arranged close to an eight-channel bias circuit at a second end; the first DC-DC chip 610 is respectively connected with an eight-channel bias circuit arranged at the first end of the circuit board and provides reverse bias voltage for the electro-absorption modulation region; the second DC-DC chip 620 is connected to an eight-channel bias circuit provided at the second end of the circuit board, respectively, to supply a reverse bias voltage to the electro-absorption modulation region.

As shown in fig. 8 and 9, in the first end of the circuit board, the first DSP chip 630 is connected to the first differential signal line, the second differential signal line, the third differential signal line, the fourth differential signal line, the fifth differential signal line, the sixth differential signal line, the seventh differential signal line, and the eighth differential signal line, respectively. In the other end, the second DSP chip 640 is connected to a ninth differential signal line, a tenth differential signal line \8230anda sixteenth differential signal line, respectively.

The circuit board comprises a circuit board, a first bias circuit, a second bias circuit, a eighth bias circuit, a differential signal line and a differential signal line, wherein the circuit board comprises a first bias circuit, a second bias circuit, a third bias circuit, a fourth bias circuit and a fourth bias circuit, the first bias circuit and the second bias circuit are connected in series, the first bias circuit and the second bias circuit are electrically connected with the corresponding differential signal line, and the second bias circuit, the third bias circuit and the fourth bias circuit are arranged on one side of the first differential signal line and are adjacent and compact; the first unit and the second unit in the first bias circuit can be directly and electrically connected through the top layer wiring of the circuit board, and the first unit and the second unit in the second bias circuit, the third bias circuit and the fourth bias circuit can be electrically connected through the through holes of the circuit board. The first unit and the second unit in the eighth bias circuit can be directly and electrically connected through the top layer wiring of the circuit board.

The first bias circuit includes a first cell 711 and a second cell 712, as shown in fig. 8 and 9, the first cell 711 and the second cell 712 are directly connected by a trace on the top layer of the circuit board; the surface of the circuit board is provided with a first magnetic bead first bonding pad, a first magnetic bead second bonding pad, a second magnetic bead first bonding pad, a second magnetic bead second bonding pad, an inductor first bonding pad, an inductor second bonding pad, a resistor first bonding pad and a resistor second bonding pad of a first bias circuit; the first magnetic bead first bonding pad and the first magnetic bead second bonding pad are used for arranging first magnetic beads, the second magnetic bead first bonding pad and the second magnetic bead second bonding pad are used for arranging second magnetic beads, the inductor first bonding pad and the inductor second bonding pad are used for arranging inductors, and the resistor first bonding pad and the resistor second bonding pad are used for arranging resistors; similarly, the second bonding pad of the first magnetic bead is connected with the first bonding pad of the second magnetic bead to realize the series connection of the first magnetic bead and the second magnetic bead; the second magnetic bead second pad is connected to the inductor first pad to realize the series connection of the first unit 711 and the second unit 712, and the first unit 711 and the second unit 712 are directly connected through the trace on the top layer of the circuit board.

The second bias circuit includes a first cell 721 and a second cell 722, and as shown in fig. 8 and 9, the first cell 721 and the second cell 722 are electrically connected through a circuit board via; the surface of the circuit board is provided with a first magnetic bead first bonding pad, a first magnetic bead second bonding pad, a second magnetic bead first bonding pad, a second magnetic bead second bonding pad, an inductor first bonding pad, an inductor second bonding pad, a resistor first bonding pad and a resistor second bonding pad of a second bias circuit; the second unit is arranged close to the second unit of the first bias circuit and is electrically connected with the first unit through a circuit board through hole.

The third bias circuit includes a first unit 731 and a second unit 732, and as shown in fig. 8 and 9, the first unit 731 and the second unit 732 are connected by a circuit board via; the surface of the circuit board is provided with a first magnetic bead first bonding pad, a first magnetic bead second bonding pad, a second magnetic bead first bonding pad, a second magnetic bead second bonding pad, an inductor first bonding pad, an inductor second bonding pad, a resistor first bonding pad and a resistor second bonding pad of a third bias circuit; the second unit is arranged next to the second unit of the second bias circuit and is electrically connected with the first unit through a circuit board through hole.

The fourth bias circuit includes a first cell 741 and a second cell 742, and as shown in fig. 8 and 9, the first cell 741 and the second cell 742 are connected by a circuit board via; the surface of the circuit board is provided with a first magnetic bead first bonding pad, a first magnetic bead second bonding pad, a second magnetic bead first bonding pad, a second magnetic bead second bonding pad, an inductor first bonding pad, an inductor second bonding pad, a resistor first bonding pad and a resistor second bonding pad of a fourth bias circuit; the second unit is arranged next to the second unit of the third bias circuit and is electrically connected with the first unit through a circuit board through hole.

The fifth bias circuit includes a first cell 751 and a second cell 752, and as shown in fig. 8 and 9, the first cell 751 and the second cell 752 are directly connected by a trace on the top layer of the circuit board; the surface of the circuit board is provided with a first magnetic bead first bonding pad, a first magnetic bead second bonding pad, a second magnetic bead first bonding pad, a second magnetic bead second bonding pad, an inductor first bonding pad, an inductor second bonding pad, a resistor first bonding pad and a resistor second bonding pad of a fifth bias circuit; the second unit is arranged at one end of the fifth differential signal line and is directly and electrically connected with the first unit through a top-layer wiring of the circuit board, similarly, the second magnetic bead second pad is directly connected with the inductor first pad to realize the series connection of the first unit and the second unit, and the first unit 751 and the second unit 752 are directly connected through the top-layer wiring of the circuit board.

The sixth bias circuit includes a first unit 761 and a second unit 762, as shown in fig. 8 and 9, the first unit 761 and the second unit 762 are directly connected by a trace on the top layer of the circuit board; the surface of the circuit board is provided with a first magnetic bead first bonding pad, a first magnetic bead second bonding pad, a second magnetic bead first bonding pad, a second magnetic bead second bonding pad, an inductor first bonding pad, an inductor second bonding pad, a resistor first bonding pad and a resistor second bonding pad of a sixth bias circuit; the second unit is arranged at one end of the sixth differential signal line and is directly and electrically connected with the first unit through the top layer wiring of the circuit board, similarly, the second magnetic bead second bonding pad is directly connected with the inductance first bonding pad to realize the series connection of the first unit and the second unit, and the first unit 761 and the second unit 762 are directly connected through the top layer wiring of the circuit board.

The seventh bias circuit includes a first cell 771 and a second cell 772, as shown in fig. 8 and 9, the first cell 771 and the second cell 772 are directly connected by traces on the top layer of the circuit board; the surface of the circuit board is provided with a first magnetic bead first bonding pad, a first magnetic bead second bonding pad, a second magnetic bead first bonding pad, a second magnetic bead second bonding pad, an inductor first bonding pad, an inductor second bonding pad, a resistor first bonding pad and a resistor second bonding pad of a seventh bias circuit; the second unit is disposed at one end of the seventh differential signal line and is directly electrically connected to the first unit through the top layer trace of the circuit board, and similarly, the second magnetic bead second pad is directly connected to the inductor first pad to realize the series connection of the first unit and the second unit, and the first unit 771 and the second unit 772 are directly connected through the top layer trace of the circuit board.

The eighth bias circuit includes a first unit cell 781 and a second unit cell 782, as shown in fig. 8 and 9, the first unit cell 781 and the second unit cell 782 are directly connected by traces on the top layer of the circuit board; the surface of the circuit board is provided with a first magnetic bead first bonding pad, a first magnetic bead second bonding pad, a second magnetic bead first bonding pad, a second magnetic bead second bonding pad, an inductor first bonding pad, an inductor second bonding pad, a resistor first bonding pad and a resistor second bonding pad of an eighth bias circuit; the second unit is arranged at one end of the eighth differential signal line and is directly and electrically connected with the first unit through the wiring on the top layer of the circuit board, similarly, the second magnetic bead second bonding pad is directly connected with the inductance first bonding pad to realize the series connection of the first unit and the second unit, and the first unit 781 and the second unit 782 are directly connected through the wiring on the top layer of the circuit board.

As shown in fig. 10 and 11, the ninth and tenth bias circuits 8230are provided in the same manner as the first and second bias circuits 8230, and the eighth bias circuit is provided.

The ninth bias circuit includes a first cell 791 and a second cell 792, the first cell 791 and the second cell 792 being directly connected by a top layer trace of the circuit board.

The tenth bias circuit includes a first cell 7101 and a second cell 7102, and the first cell 7101 and the second cell 7102 are connected through a circuit board via.

The eleventh bias circuit includes a first cell 7111 and a second cell 7112, and the first cell 7111 and the second cell 7112 are connected through a circuit board via.

The twelfth bias circuit includes a first unit 7121 and a second unit 7122, and the first unit 7121 and the second unit 7122 are connected through a circuit board via.

The thirteenth bias circuit includes a first cell 7131 and a second cell 7132, and the first cell 7131 and the second cell 7132 are directly connected by top layer traces of the circuit board.

The fourteenth bias circuit includes a first unit 7141 and a second unit 7142, and the first unit 7141 and the second unit 7142 are directly connected through the top layer trace of the circuit board.

The fifteenth bias circuit includes a first cell 7151 and a second cell 7152, in which the first cell 7151 and the second cell 7152 are directly connected by a top layer trace of the circuit board.

The sixteenth biasing circuit includes a first unit 7161 and a second unit 7162, and the first unit 7161 and the second unit 7162 are directly connected through the top layer trace of the circuit board.

The inexhaustible structure of each first unit in the 16-channel optical module refers to the structure of each first unit of the eight-channel optical module, and the structures are in the same setting relationship; the structures of the second units in the 16-channel optical module are not the most, the structures of the second units in the eight-channel optical module are referred to, and the arrangement relationship of the structures is the same.

As seen from the above description of the arrangement manner of the 16-channel optical module bias circuit, in the embodiment of the present application, the bias circuit of each channel includes the first unit and the second unit, and in order to set a plurality of bias circuits on a limited circuit board space, the second unit and the second unit in the bias circuit may be centrally located at the same position, or may be separately located; when the first unit and the second unit in the bias circuit are intensively arranged at the same position, the first unit and the second unit can be directly electrically connected through the wiring on the top layer of the circuit board, such as a first bias circuit and a fifth bias circuit; when the first unit and the second unit in the bias circuit are not arranged together but are arranged separately, the first unit and the second unit are electrically connected through the circuit board through hole; therefore, the bias circuits are compactly and reasonably arranged on the circuit board, mutual crosstalk among the bias circuits is avoided, the generated parasitic capacitance is reduced, and the normal work of the bias circuits of the optical module is ensured.

In summary, in the embodiment of the application, the surface of the circuit board is provided with a DC-DC chip and a bias circuit, the light emitting device comprises a laser, the laser comprises an electro-absorption modulation region, the DC-DC chip provides a reverse bias voltage to the electro-absorption modulation region through the bias circuit, and simultaneously the DSP chip provides a modulation signal to the electro-absorption modulation region; the electro-absorption modulation region modulates light under a modulation signal and a reverse bias voltage. The bias circuit comprises a first unit and a second unit, wherein the first unit comprises a first magnetic bead and a second magnetic bead; the second unit includes an inductance and a resistance. When the optical module is in multiple channels, the first units and the second units in some channels can be electrically connected through routing on the surface of the circuit board, and the first units and the second units in other channels can be electrically connected through via holes between the surface of the circuit board and the intermediate layer, so that mutual crosstalk among the channels is avoided, reasonable layout is realized, parasitic capacitance is reduced, and the working performance of the optical module is ensured.

The above description is only for the specific embodiments of the present disclosure, but the scope of the present disclosure is not limited thereto, and any person skilled in the art will appreciate that changes or substitutions within the technical scope of the present disclosure are included in the scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be subject to the protection scope of the claims.

Claims

1. A light module, comprising:

the surface of the circuit board is provided with a DC-DC chip;

the laser, including:

a light emitting region for emitting light not carrying data;

2. The optical module according to claim 1, wherein the circuit board surface is provided with a first bias circuit, a second bias circuit, a third bias circuit, a fourth bias circuit, a fifth bias circuit, a sixth bias circuit, a seventh bias circuit, and an eighth bias circuit, respectively;

the first bias circuit, the second bias circuit, the third bias circuit, the fourth bias circuit, the fifth bias circuit, the sixth bias circuit, the seventh bias circuit and the eighth bias circuit respectively comprise a first unit and a second unit;

the surface of the circuit board is respectively provided with a first differential signal line, a second differential signal line, a third differential signal line, a fourth differential signal line, a fifth differential signal line, a sixth differential signal line, a seventh differential signal line and an eighth differential signal line.

3. The optical module according to claim 2, wherein the first magnetic bead and the second magnetic bead are connected in series;

the first magnetic bead of the first bias circuit is electrically connected with the first differential signal line;

the first magnetic bead of the second bias circuit is electrically connected with the second differential signal line;

the first magnetic bead of the third bias circuit is electrically connected with the third differential signal line;

the first magnetic bead of the fourth bias circuit is electrically connected with the fourth differential signal line;

the first magnetic bead of the fifth bias circuit is electrically connected with the fifth differential signal line;

the first magnetic bead of the sixth bias circuit is electrically connected with the sixth differential signal line;

the first magnetic bead of the seventh bias circuit is electrically connected with the seventh differential signal line;

the first magnetic bead of the eighth bias circuit is electrically connected to the eighth differential signal line.

4. The optical module according to claim 3, wherein the second unit of the first bias circuit, the second unit of the second bias circuit, and the second unit of the third bias circuit are all provided on one side of the first differential signal line;

the second unit of the fourth bias circuit and the second unit of the fifth bias circuit are arranged between the fourth differential signal line and the fifth differential signal line;

the second unit of the sixth bias circuit, the second unit of the seventh bias circuit, and the second unit of the eighth bias circuit are all disposed at one side of the eighth differential signal line.

5. The optical module of claim 4, wherein the first and second cells of the first bias circuit are electrically connected by wire bonding on a top layer of the circuit board;

the first unit and the second unit in the fifth bias circuit are electrically connected through routing of the top layer of the circuit board;

and the first units and the second units in the second bias circuit, the third bias circuit, the fourth bias circuit, the sixth bias circuit, the seventh bias circuit and the eighth bias circuit are electrically connected through via holes of a circuit board.

6. The light module of claim 5, wherein the circuit board comprises a top layer, an intermediate layer, and a bottom surface;

the middle layer comprises a second layer, a third layer and a fourth layer;

the second layer is a grounding layer;

the through hole is arranged between the top layer and the third layer.

7. The light module of claim 1, wherein the circuit board surface is provided with:

and the filter capacitor is connected with the bias circuit in parallel, one end of the filter capacitor is connected with the second unit, and the other end of the filter capacitor is grounded.

8. The optical module according to claim 1, wherein a first bead pad is disposed on each of the differential signal line and the circuit board surface, and is used for disposing two ends of the first bead;

the first magnetic bead bonding pad on the differential signal line is oval, and the first magnetic bead bonding pad on the surface of the circuit board is square.

9. The optical module according to claim 1, wherein one end of the circuit board is provided with a gold finger;

the golden finger comprises a power supply pin;

and the input end of the DC-DC chip is electrically connected with the power supply pin, and the output end of the DC-DC chip is electrically connected with the second unit and used for outputting negative bias voltage.

10. The light module of claim 1,

the cathode of the electroabsorption modulation region is grounded;

and the positive electrode of the electro-absorption modulation region is electrically connected with the DSP chip and the bias circuit respectively.