CN217406549U - Optical module - Google Patents

Abstract

The optical module that this application embodiment provided, including the circuit board, the laser instrument of being connected with the circuit board electricity, laser driver chip and single-ended resistance, the single-ended impedance of laser driver chip is greater than the single-ended impedance of laser instrument, laser driver chip includes positive modulation current output end, negative modulation current output end, wherein the one end of negative modulation current output end and single-ended resistance all is connected with laser instrument negative pole electricity, and the other end of single-ended resistance other end and laser driver chip all grounds, consequently, single-ended resistance forms the parallel relation with laser driver chip, can reduce the impedance of laser driver chip through single-ended resistance and laser driver chip are parallelly connected, and then the impedance continuity of multiplicable and laser instrument, improve high frequency performance.

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 realizes the function of photoelectric conversion in the technical field of optical communication, is one of key devices in optical communication equipment, and the intensity of an optical signal input into an external optical fiber by the optical module directly influences the quality of optical fiber communication.

The optical module comprises a light emitting component and a light receiving component, the light emitting component comprises a laser driving chip and a laser, the laser driving chip provides a driving signal for the laser to enable the laser to emit a light signal, and in practical application, when the impedance of the laser driving chip is discontinuous with the impedance of the laser, the transmission quality of the signal can be reduced, so that the high-frequency performance is reduced.

SUMMERY OF THE UTILITY MODEL

The application provides an optical module to improve impedance continuity between a laser driving chip and a laser.

The optical module provided by the embodiment of the application comprises:

a circuit board;

the laser is electrically connected with the circuit board;

the laser driving chip is electrically connected with the circuit board and comprises a positive modulation current output end, a negative modulation current output end and a bias current output end, the positive modulation current output end is electrically connected with the positive electrode of the laser, the negative modulation current output end and the bias current output end are both electrically connected with the negative electrode of the laser, and the differential impedance is greater than the laser impedance;

and the single-ended resistor is electrically connected with the circuit board, one end of the single-ended resistor is electrically connected with the negative electrode of the laser, and the other end of the single-ended resistor is grounded.

The optical module that this application embodiment provided, the circuit board comprises a circuit board, the laser instrument of being connected with the circuit board electricity, laser driver chip and single-ended resistance, laser driver chip's differential impedance is greater than the laser instrument impedance, laser driver chip includes positive modulation current output, negative modulation current output, wherein negative modulation current output all is connected with laser instrument negative pole electricity with the one end of single-ended resistance, and the single-ended resistance other end and laser driver chip all ground connection, consequently, single-ended resistance forms the parallel relation with laser driver chip, can reduce laser driver chip's impedance through single-ended resistance and laser driver chip are parallelly connected, and then the impedance continuity of multiplicable and laser instrument, improve high frequency performance.

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 considered 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 an internal structure of a light module according to some embodiments;

FIG. 6 is a schematic diagram of a light emitting assembly in relation to a flexible circuit board according to some embodiments;

FIG. 7 is a schematic diagram of an internal structure of a light emitting assembly according to some embodiments;

FIG. 8 is a schematic circuit diagram between a laser driver chip and a laser according to some embodiments;

FIG. 9 is a schematic diagram of a structure of a surface of a flexible circuit board according to some embodiments;

fig. 10 is a schematic diagram of another surface of a flexible circuit board according to some embodiments.

Detailed Description

Technical solutions in some embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are only a part of the embodiments of the present disclosure, and not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments provided by the present disclosure belong to the protection scope of the present disclosure.

Unless the context requires otherwise, throughout the description and the claims, the term "comprise" and its other forms, such as the third person's singular form "comprising" and the present participle form "comprising" are to be interpreted in an open, inclusive sense, i.e. as "including, but not limited to". In the description of the specification, the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" and the like are intended to indicate that a particular feature, structure, material, or characteristic associated with the embodiment or example is included in at least one embodiment or example of the present disclosure. The schematic representations of the terms used above are not necessarily referring to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be included in any suitable manner in any one or more embodiments or examples.

In the following, the terms "first", "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the embodiments of the present disclosure, "a plurality" means two or more unless otherwise specified.

In describing some embodiments, expressions of "coupled" and "connected," along with their derivatives, may be used. For example, the term "connected" may be used in describing some embodiments to indicate that two or more elements are in direct physical or electrical contact with each other. As another example, some embodiments may be described using the term "coupled" to indicate that two or more elements are in direct physical or electrical contact. However, the terms "coupled" or "communicatively coupled" may also mean that two or more elements are not in direct contact with each other, but yet still co-operate or interact with each other. The embodiments disclosed herein are not necessarily limited to the contents herein.

"at least one of A, B and C" has the same meaning as "A, B or at least one of C," each including the following combination of A, B and C: a alone, B alone, C alone, a combination of a and B, a combination of a and C, a combination of B and C, and a combination of A, B and C.

"A and/or B" includes the following three combinations: a alone, B alone, and a combination of A and B.

The use of "adapted to" or "configured to" herein is meant to be an open and inclusive language that does not exclude devices adapted to or configured to perform additional tasks or steps.

As used herein, "about," "approximately," or "approximately" includes the stated values as well as average values that are within an acceptable range of deviation for the particular value, as determined by one of ordinary skill in the art in view of the measurement in question and the error associated with measurement of the particular quantity (i.e., the limitations of the measurement system).

In the optical communication technology, light is used to carry information to be transmitted, and an 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. Because the optical signal has the passive transmission characteristic when being transmitted through the optical fiber or the optical waveguide, the information transmission with low cost and low loss 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 fiber communication. The optical module comprises an optical port and an electrical 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 electrical connection with an optical network terminal (such as an optical modem) through the electrical port, and the electrical connection is mainly used for realizing power supply, I2C signal transmission, data signal 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 according to some embodiments. As shown in fig. 1, the optical communication system mainly 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 several kilometers (6 kilometers to 8 kilometers), on the basis of which if a repeater is used, ultra-long-distance transmission can be theoretically achieved. 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 device 2000 and the remote server 1000 is completed 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 and an electrical port. The optical port is configured to connect with the optical fiber 101, so 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 a 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.

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 an electrical signal from the optical module 200 to the network cable 103, and transmits a 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) and the like 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 an optical network terminal according to some embodiments, and fig. 2 only shows a structure of the optical module 100 related to the optical module 200 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 PCB circuit board 105 disposed in the housing, a cage 106 disposed on a surface of the PCB circuit board 105, 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, an electrical port of the optical module 200 is connected to an electrical connector inside the cage 106, and the optical module 200 establishes a bidirectional electrical signal connection with the onu 100. Further, the optical port of the optical module 200 is connected to the optical fiber 101, and the optical module 200 establishes bidirectional electrical signal connection with the optical fiber 101.

Fig. 3 is a block diagram of a light module according to some embodiments, and fig. 4 is an exploded view of a light module according to some embodiments. As shown in fig. 3 and 4, the optical module 200 includes a housing, a circuit board 105 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 204 and 205; the outer contour of the housing generally appears square.

In some embodiments of the present disclosure, the lower housing 202 includes a bottom plate and two lower side plates located at two sides of the bottom plate and disposed perpendicular to the bottom plate; the upper housing 201 includes a cover plate, and two upper side plates disposed on two sides of the cover plate and perpendicular to the cover plate, and is combined with the two side plates by two side walls to cover the upper housing 201 on the lower housing 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 (left end in fig. 3) of the optical module 200, and the opening 205 is also located at an end (right 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. Wherein, the opening 204 is an electrical port, and the gold finger of the circuit board 105 extends out of the opening 204 and is inserted into an upper computer (such as the optical network terminal 100); the opening 205 is an optical port configured to receive an external optical fiber 101 so that the 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 assemble the circuit board 105, the optical transceiver module and other devices in the shell, and the upper shell 201 and the lower shell 202 can form package protection for the devices. In addition, when the devices such as the circuit board 105 and the like are assembled, the positioning components, the heat dissipation components and the electromagnetic shielding components of the devices are convenient to arrange, and the automatic implementation production is facilitated.

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

In some embodiments, the optical module 200 further includes an unlocking component 203 located on an outer wall of the housing of the optical module, and the unlocking component 203 is configured to implement a fixed connection between the optical module 200 and an upper computer or release the fixed connection between the optical module 200 and the upper computer.

Illustratively, the unlocking members 203 are located on the outer walls of the two lower side plates of the lower housing 202, and include snap-fit members that mate with a cage of an upper computer (e.g., 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 203; when the unlocking member 203 is pulled, the engaging member of the unlocking member 203 moves along with the unlocking member, and the connection relationship between the engaging member and the upper computer is changed, so that the engagement 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 105 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. The electronic components may include, for example, capacitors, resistors, transistors, Metal-Oxide-Semiconductor Field-Effect transistors (MOSFETs). The chip may include, for example, a Micro Controller Unit (MCU), 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 105 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 a chip; the rigid circuit board can also be inserted into an electric connector in the cage of the upper computer.

The circuit board 105 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 105 is inserted into the cage 106 and electrically connected to an electrical connector in the cage 106 by gold fingers. The gold fingers may be disposed on only one side of the circuit board 105 (e.g., the upper surface shown in fig. 4), or may be disposed on both the upper and lower sides of the circuit board 105, 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.

Fig. 5 is a schematic view of an internal structure of an optical module according to an embodiment of the present application. As shown in fig. 5, in the optical module provided in this embodiment, the optical transceiver module 300 includes a circular-square tube 310, and the light emitting module 400 and the light receiving module 500 embedded on the circular-square tube 310 are disposed on the circular-square tube 310; the light emitting module 400 and the light receiving module 500 are respectively electrically connected to the circuit board 105, so that the light emitting module 400 is used for outputting signal light and the light receiving module 500 is used for receiving signal light from the outside of the optical module, thereby realizing electro-optical and photoelectric conversion of the optical module; the round and square tube 310 is usually provided with a lens assembly for changing the propagation direction of the output signal light of the optical transmission assembly 400 or the input signal light of the external optical fiber.

Fig. 7 is a block diagram of a light emitting module 400 according to an embodiment of the present application, and as shown in fig. 7, a laser 430 is disposed on the other side of a stem 410; the pins arranged on the tube seat 410 penetrate from one side of the tube seat 410 to the other side of the tube seat 410; the laser 430 can be connected with a corresponding pin through routing, then the circuit board is electrically connected with the flexible circuit board 600 electrically connected with the pin, the flexible circuit board 600 is provided with metal wiring, and then power supply or signal transmission and the like are realized for the laser 430 and other electric devices in the light emitting assembly 400 through the flexible circuit board 600.

The surface of the circuit board 105 is provided with a laser driving chip, and the surface of the circuit board 105 is provided with a driving pad to arrange the laser driving chip. As shown in fig. 8, the laser driver chip includes a positive modulation current output terminal, a negative modulation current output terminal, and a bias current output terminal, and accordingly, the laser driver chip is provided with a positive modulation current output pin, a negative modulation current output pin, and a bias current output pin to output a positive modulation current, a negative modulation current, and a bias current to the laser, respectively, and the positive modulation current and the negative modulation current provide a high-frequency signal for the laser; the bias current drives the laser to emit light, and a high-frequency signal is modulated into a light beam generated by the laser to generate signal light. When the impedance of the laser driving chip is not continuous with the impedance of the laser, the transmission of signals is affected.

In some embodiments of the present application, the light emitting module 400 and the light receiving module 500 are respectively connected to corresponding flexible circuit boards 600, the structure of the flexible circuit boards 600 can be referred to in fig. 6, the flexible circuit boards 600 are electrically connected to the circuit board 105, and thus the electrical connection between the electrical components in the light emitting module 400 and the light receiving module 500 and the circuit board 105 is realized through the corresponding flexible circuit boards.

In this embodiment, the flexible circuit board 600 includes a first surface 610 and a second surface 620, the first surface 610 may be a top surface of the flexible circuit board 600, the second surface 620 may be a bottom surface of the flexible circuit board 600, a second connection portion 640 is disposed on a side of the flexible circuit board 600 close to the circuit board, a first connection portion 630 is disposed on a side close to the light emitting assembly, a pad region is disposed in a region of the second connection portion 640 of the first surface 610, the pad region includes a second ground pad 641, a first high-frequency signal pad 642, a second high-frequency signal pad 643 and a second low-frequency signal pad 644, a positive modulation current emitted by the laser driver chip is transmitted to a positive electrode of the laser through the first high-frequency signal pad 642, a negative modulation current emitted by the laser driver chip is transmitted to a negative electrode of the laser through the second high-frequency signal pad 643, a bias current emitted by the laser driver chip is transmitted to the negative electrode of the laser through the second low-frequency signal pad 644, further, a forward modulation current output end of the laser driving chip is electrically connected to the first high-frequency signal pad 642 to transmit a forward modulation current; a negative modulation current output end of the laser driving chip is electrically connected to the second high-frequency signal pad 643 to transmit a negative modulation current; the bias current output terminal of the laser driving chip is electrically connected to the second low-frequency signal pad 644 to transmit a bias current signal.

As shown in fig. 9, a laser positive pin through hole 631, a laser positive signal pad 632, a laser negative pin through hole 633, a laser negative signal pad 634, a low-frequency signal pin through hole 635 and a first low-frequency signal pad 636 are arranged in the first connection portion 630 region of the first surface 610; the forward modulation current output end of the laser driving chip is electrically connected with a first high-frequency signal bonding pad 642, and the first high-frequency signal bonding pad 642 is electrically connected with a laser anode signal bonding pad 632 so as to transmit the forward modulation current generated by the laser driving chip to the laser anode; the negative modulation current output end of the laser driving chip is electrically connected with the second high-frequency signal pad 643, and the second high-frequency signal pad 643 is electrically connected with the laser cathode signal pad 634, so that the negative modulation current generated by the laser driving chip is transmitted to the laser cathode; the bias current output end of the laser driving chip is electrically connected with a second low-frequency signal pad 644, and the second low-frequency signal pad 644 is electrically connected with a first low-frequency signal pad 636, so that the bias current generated by the laser driving chip is transmitted to the laser. Then, the bias current drives the laser to emit light, and the positive modulation current signal and the negative modulation current signal are modulated into a light beam generated by the laser to generate a light beam carrying signals. In some examples, a first differential signal trace is disposed between the positive modulation current output of the laser driver chip and the laser positive signal pad 632, and a second differential signal trace is disposed between the negative modulation current output of the laser driver chip and the laser negative signal pad 634.

Further, as can be seen from fig. 6, the tube seat is provided with a plurality of pins, including a laser anode pin, a laser cathode pin, a low-frequency signal pin and a ground pin, the laser anode pin passes through the laser anode pin through hole 631 and is connected with the laser anode signal pad 632 in a welding manner; the laser cathode pin penetrates through the laser cathode pin through hole 633 and is connected with the laser cathode signal pad 634 in a welding mode; the low frequency signal pin passes through the low frequency signal pin through hole 635 and is solder-connected to the first low frequency signal pad 636.

The tube seat is also provided with a grounding pin which passes through the grounding through hole 637 and is connected with the first grounding pad 638 in a welding manner to realize the grounding of the device; the second surface 620 area of the flexible circuit board is further provided with a ground layer 621, the ground layer 621 is configured as shown in fig. 10, the ground via 637 is filled with a metal layer formed by a metal material, the metal layer is electrically connected to the ground layer 621 on the second metal layer, then the ground layer 621 is electrically connected to the second ground pad 641, the second ground pad 641 is electrically connected to a corresponding ground pad on the circuit board, when the second ground pad 641 is disposed on the second surface 620, the ground layer 621 is electrically connected to the second ground pad 641 by wire bonding, and when the second ground pad 641 is disposed on the first surface 610, the ground layer 621 and the second ground pad 641 are electrically connected through a metal via.

In the embodiment of the present application, the area of the ground layer 621 is relatively large, so to increase the contact area between the ground via 637 and the ground pin, the opening area of the ground via 637 is relatively large, and more tin may be deposited on the ground pin during soldering. The opening area of the ground via 637 is larger than the opening areas of the laser positive pin via 631, the laser negative pin via 633, and the low-frequency signal pin via 635, and the shape of the ground via 637 can be selected in accordance with the actual shape and space of the first connection portion 630.

As mentioned above, when the impedance of the laser driving chip is discontinuous with the impedance of the laser, the transmission of signals is affected, and further the high-frequency performance of the optical module is affected; in some embodiments, the impedance of the laser driver chip is greater than the impedance of the laser, e.g., the differential impedance of the laser driver chip is 100 Ω, and the impedance of the laser is 50 Ω; to this end, the embodiment of the present application provides a single-ended resistor R0, as shown in fig. 8, one end of the single-ended resistor R0 is electrically connected to the laser cathode, further, one end of the single-ended resistor R0 is electrically connected to the laser cathode signal pad, the other end is grounded, and further, the other end is electrically connected to the first ground pad 638; because the negative modulation current output end of the laser driving chip is also electrically connected to the negative electrode of the laser, namely the negative signal pad of the laser, the laser driving chip and the single-ended resistor R0 are in parallel connection, and the impedance of the laser driving chip can be reduced by connecting the single-ended resistor R0 and the laser driving chip in parallel, so that the impedance continuity with the laser can be improved, and the high-frequency performance is improved.

As mentioned above, in some embodiments, the single-ended impedance of the laser driver chip is greater than the single-ended impedance of the laser, for example, the differential impedance of the laser driver chip is 100 Ω, and the impedance of the laser is 50 Ω, which can be understood as the differential impedance of the laser; in an ideal situation, the single-ended impedance of the laser driver chip is 50 Ω, and the single-ended impedance of the laser is 25 Ω, so in this embodiment of the application, the resistance of the single-ended resistor R0 is in the range of 50 Ω to 60 Ω, and optionally, the resistance of the single-ended resistor R0 is 50 Ω, so that the equivalent resistor after the laser driver chip is connected in parallel with the laser driver chip through the single-ended resistor R0 is 25 Ω, and the single-ended impedance of the laser is 25 Ω, so that the single-ended impedance of the laser driver chip is continuous with the single-ended impedance of the laser, thereby improving the transmission quality of high-frequency signals and improving the high-frequency performance.

Therefore, when the single-end impedance of the laser driving chip and the laser which are matched with each other is discontinuous, the impedance continuity of the laser driving chip and the laser can be improved through the application, and the feasibility of matching the laser driving chip and the laser with discontinuous impedance is improved.

In order to improve the flatness of the laser, a resistor R1 and a resistor R2 are respectively connected in series on high-frequency links at the positive end and the negative end of the laser, specifically, a first resistor is arranged on a routing line between the laser and a positive pin of the laser in a cavity formed by a tube seat and a tube cap, and a second resistor is arranged on a routing line between the laser and a negative pin of the laser, so that the high-frequency performance is improved; optionally, the resistances of the resistor R1 and the resistor R2 are the same, such as 10 Ω.

The optical module that this application embodiment provided, which comprises a circuit board, the laser instrument of being connected with the circuit board electricity, laser driver chip and single-ended resistance, laser driver chip's single-ended impedance is greater than the single-ended impedance of laser instrument, laser driver chip includes positive modulation current output end, negative modulation current output end, wherein negative modulation current output end all is connected with laser instrument negative pole electricity with the one end of single-ended resistance, and the single-ended resistance other end and laser driver chip all ground connection, therefore, single-ended resistance forms the parallel relation with laser driver chip, can reduce laser driver chip's impedance through single-ended resistance and laser driver chip are parallelly connected, and then the impedance continuity with the multiplicable laser instrument, improve high frequency performance.

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 should be covered by the scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the protection scope of the claims.

Claims (10)

1. A light module, comprising:

a circuit board;

a laser electrically connected to the circuit board;

the laser driving chip is electrically connected with the circuit board and comprises a positive modulation current output end, a negative modulation current output end and a bias current output end, the positive modulation current output end is electrically connected with the positive pole of the laser, the negative modulation current output end and the bias current output end are both electrically connected with the negative pole of the laser, and the differential impedance is greater than the impedance of the laser;

and the single-ended resistor is electrically connected with the circuit board, one end of the single-ended resistor is electrically connected with the negative electrode of the laser, and the other end of the single-ended resistor is grounded.

2. The optical module of claim 1, comprising:

the flexible circuit board is used for electrically connecting the laser driving chip and the laser, and comprises:

the first metal layer is arranged on one surface of the flexible circuit board, and the surface is provided with:

the laser anode signal bonding pad is electrically connected with the laser;

the laser cathode signal bonding pad is electrically connected with the laser;

one end of the first high-frequency signal bonding pad is electrically connected with the forward modulation current output end, and the other end of the first high-frequency signal bonding pad is electrically connected with the laser anode signal bonding pad;

one end of the second high-frequency signal bonding pad is electrically connected with the negative modulation current output end, and the other end of the second high-frequency signal bonding pad is electrically connected with the laser cathode signal bonding pad;

and the low-frequency signal pad is electrically connected with the bias current output end.

3. The optical module of claim 1, wherein one end of the single-ended resistor is electrically connected to the laser cathode signal pad, and the other end is grounded.

4. The optical module according to claim 1, wherein the impedance of the laser is 50 Ω, the differential impedance of the laser driver chip is 100 Ω, and the resistance of the single-ended resistor is 50 Ω to 60 Ω.

5. The optical module according to claim 4, wherein the impedance of the laser is 50 Ω, the differential impedance of the laser driver chip is 100 Ω, and the resistance of the single-ended resistor is 50 Ω.

6. The optical module of claim 2, wherein the optical module comprises an optical transmission assembly, the optical transmission assembly comprises a tube socket and a tube cap, and the tube socket is provided with a laser positive pin and a laser negative pin;

in a cavity formed by the tube seat and the tube cap, a first resistor is arranged on a routing between the laser and the anode pin of the laser, and a second resistor is arranged on a routing between the laser and the cathode pin of the laser;

the first resistor and the second resistor have the same resistance value.

7. The optical module of claim 2, wherein a first differential signal trace is disposed between the positive modulation current output terminal and the laser positive signal pad, and a second differential signal trace is disposed between the negative modulation current output terminal and the laser negative signal pad.

8. The optical module according to claim 6, wherein the flexible circuit board further comprises a second metal layer, the second metal layer is disposed on the other surface of the flexible circuit board, and a ground layer is disposed on the surface of the second metal layer;

a first grounding bonding pad is further arranged on the surface of the first metal layer, and a grounding through hole is formed around the first grounding bonding pad;

the first ground pad is electrically connected to the ground via, which is electrically connected to the ground layer.

9. The optical module of claim 8, wherein the base has a ground pin;

the flexible circuit board is provided with a laser anode pin through hole, a laser cathode pin through hole and a grounding through hole;

the laser anode pin penetrates through the laser anode pin through hole and is electrically connected with the laser anode signal bonding pad;

the laser cathode pin penetrates through the laser cathode pin through hole and is electrically connected with the laser cathode signal bonding pad;

the grounding pin penetrates through the grounding through hole and is electrically connected with the first grounding pad.

10. The optical module of claim 8, wherein the single-ended resistor is electrically connected to the laser cathode signal pad at one end and to the first ground pad at another end.

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