CN212543787U - Optical module - Google Patents
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- CN212543787U CN212543787U CN202021135040.4U CN202021135040U CN212543787U CN 212543787 U CN212543787 U CN 212543787U CN 202021135040 U CN202021135040 U CN 202021135040U CN 212543787 U CN212543787 U CN 212543787U
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Abstract
An optical module includes a circuit board and a light emitting assembly electrically connected to the circuit board. The light emitting assembly includes an EML laser. The circuit board is provided with an MCU, a first resistor, an operational amplifier, a second resistor, a triode, a first feedback circuit and a second feedback circuit. The MCU sends a voltage signal, the voltage signal is amplified by the operational amplifier and then is input into the base electrode of the triode, and the collector electrode and the emitter electrode of the triode are controlled to be conducted, so that the emitter electrode of the triode can send current. According to the EML laser, the MCU, the resistors, the operational amplifier, the triode and the two feedback circuits are arranged, so that the adjustable stable current only related to the voltage and each resistance value sent by the MCU can be output, and the adjustable stable current is provided for the EML laser; because the components are arranged on the circuit board, only a small amount of PCB space is occupied, and the PCB space is not limited.
Description
Technical Field
The application relates to the technical field of optical fiber communication, in particular to an optical module.
Background
Optical module products tend to be high-speed, small-package, low-cost, and for high-speed, long-distance transmission products, an EML (Electro Absorption Modulated Laser) Laser is required. Since the EML laser requires a stable current, an adjustable stable current source needs to be provided on the circuit board to supply power to the EML laser.
A typical EML laser uses a special current source chip as a stable current source. Such an EML laser using a dedicated current source chip as a stable current source may face a problem of limited PCB board space.
SUMMERY OF THE UTILITY MODEL
The application provides an optical module, which solves the problem that the space of a PCB (printed circuit board) is limited due to the use of a special current source chip.
A light module, comprising:
a circuit board;
the light emitting component comprises an EML laser and is electrically connected with the circuit board;
the circuit board is provided with:
the MCU is used for sending a voltage signal;
the input end of the first resistor is electrically connected with the output end of the MCU;
the first input end of the operational amplifier is electrically connected with the output end of the first resistor and is used for amplifying the voltage signal input by the first input end;
the input end of the second resistor is electrically connected with the second input end of the operational amplifier, and the output end of the second resistor is grounded;
the base electrode of the triode is electrically connected with the output end of the operational amplifier, and the collector electrode of the triode is connected with the power supply and used for emitting stable current according to the voltage output by the operational amplifier;
the input end of the third resistor is electrically connected with the emitting electrode of the triode, and the output end of the third resistor is electrically connected with the EML laser;
the input end of the first feedback circuit is electrically connected with the input end of the third resistor, and the output end of the first feedback circuit is electrically connected with the input end of the second resistor;
and the input end of the second feedback circuit is electrically connected with the output end of the third resistor, and the output end of the second feedback circuit is electrically connected with the output end of the first resistor.
A light module, comprising:
a circuit board;
the light emitting component comprises an EML laser and is electrically connected with the circuit board;
the circuit board is provided with:
the MCU is used for sending a voltage signal;
the input end of the first resistor is electrically connected with the output end of the MCU;
the first input end of the operational amplifier is electrically connected with the output end of the first resistor and is used for amplifying the voltage signal input by the first input end;
the input end of the second resistor is electrically connected with the second input end of the operational amplifier, and the output end of the second resistor is grounded;
the grid electrode of the MOS tube is electrically connected with the output end of the operational amplifier, and the drain electrode of the MOS tube is connected with the power supply and used for sending out stable current according to the voltage output by the operational amplifier;
the input end of the third resistor is electrically connected with the source electrode of the MOS tube, and the output end of the third resistor is electrically connected with the EML laser;
the input end of the first feedback circuit is electrically connected with the input end of the third resistor, and the output end of the first feedback circuit is electrically connected with the input end of the second resistor;
and the input end of the second feedback circuit is electrically connected with the output end of the third resistor, and the output end of the second feedback circuit is electrically connected with the output end of the first resistor.
Has the beneficial effects that; an optical module includes a circuit board and a light emitting assembly electrically connected to the circuit board. The light emitting assembly includes an EML laser. The circuit board is provided with an MCU, a first resistor, an operational amplifier, a second resistor, a triode, a first feedback circuit and a second feedback circuit. And the input end of the first resistor is electrically connected with the output end of the MCU. And the first input end of the operational amplifier is electrically connected with the output end of the first resistor. And the input end of the second resistor is electrically connected with the second input end of the operational amplifier, and the output end of the second resistor is grounded. And the base electrode of the triode is electrically connected with the output end of the operational amplifier, and the collector electrode of the triode is connected with the power supply and used for emitting stable current according to the voltage output by the operational amplifier. And the input end of the third resistor is electrically connected with the emitting electrode of the triode, and the output end of the third resistor is electrically connected with the EML laser. And the input end of the first feedback circuit is electrically connected with the input end of the third resistor, and the output end of the first feedback circuit is electrically connected with the input end of the second resistor. And the input end of the second feedback circuit is electrically connected with the output end of the third resistor, and the output end of the second feedback circuit is electrically connected with the output end of the first resistor. The MCU sends a voltage signal, after the voltage signal is divided by the first resistor, only part of the voltage signal is input into the first input end of the operational amplifier, after the voltage signal is amplified by the operational amplifier, the voltage output by the operational amplifier is input into the base electrode of the triode, the collector electrode and the emitter electrode of the triode are controlled to be conducted, so that the emitter electrode of the triode sends current, part of the current is input into the second input end of the operational amplifier through the first feedback circuit, and part of the current flows to the EML laser through the third resistor. The current flowing through the third resistor flows partly to the EML laser and partly to the second feedback circuit. Because the resistance values of the first feedback circuit and the second feedback circuit are large, the current flowing through the first feedback circuit and the second feedback circuit is ignored, and the current flowing through the fifth resistor is equal to the current flowing through the EML laser. The current flowing through the fifth resistor is obtained through calculation of the first feedback circuit and the second feedback circuit and is only related to the voltage emitted by the MCU and the resistance values of the resistors, so that the current flowing through the fifth resistor is adjustable stable current, namely the current flowing through the EML laser is adjustable stable current. According to the EML laser, the MCU, the resistors, the operational amplifier, the triode and the two feedback circuits are arranged, so that the adjustable stable current only related to the voltage and each resistance value sent by the MCU can be output, and the adjustable stable current is provided for the EML laser; because the components are arranged on the circuit board, only a small amount of PCB space is occupied, and the PCB space is not limited. In addition, in the application, a stable power supply can be formed by only a few devices without a special power supply chip, so that the cost of the optical module is effectively reduced.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is a schematic diagram of a connection relationship of an optical communication terminal;
FIG. 2 is a schematic diagram of an optical network unit;
fig. 3 is a schematic structural diagram of an optical module according to an embodiment of the present disclosure;
fig. 4 is an exploded structural diagram of an optical module according to an embodiment of the present application;
fig. 5 is a block diagram of an EML laser according to an embodiment of the present disclosure;
fig. 6 is a schematic structural diagram of a circuit board according to an embodiment of the present disclosure;
fig. 7 is a circuit diagram of a circuit board provided in an embodiment of the present application;
fig. 8 is another circuit diagram of a circuit board according to an embodiment of the present disclosure.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
One of the core links of optical fiber communication is the interconversion of optical and electrical signals. The optical fiber communication uses optical signals carrying information to transmit in information transmission equipment such as optical fibers/optical waveguides, and the information transmission with low cost and low loss can be realized by using the passive transmission characteristic of light in the optical fibers/optical waveguides; meanwhile, the information processing device such as a computer uses an electric signal, and in order to establish 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, it is necessary to perform interconversion between the electric signal and the optical signal.
The optical module realizes the function of interconversion of optical signals and electrical signals in the technical field of optical fiber communication, and the interconversion of the optical signals and the electrical signals is the core function of the optical module. The optical module is electrically connected with an external upper computer through a golden finger on an internal circuit board of the optical module, and the main electrical connection comprises power supply, I2C signals, data signals, grounding and the like; the electrical connection mode realized by the gold finger has become the mainstream connection mode of the optical module industry, and on the basis of the mainstream connection mode, the definition of the pin on the gold finger forms various industry protocols/specifications.
Fig. 1 is a schematic diagram of connection relationship of an optical communication terminal. As shown in fig. 1, the connection of the optical communication terminal mainly includes the interconnection among the optical network terminal 100, the optical module 200, the optical fiber 101 and the network cable 103;
one end of the optical fiber 101 is connected with a far-end server, one end of the network cable 103 is connected with local information processing equipment, and the connection between the local information processing equipment and the far-end server is completed by the connection between the optical fiber 101 and the network cable 103; and the connection between the optical fiber 101 and the network cable 103 is made by the optical network terminal 100 having the optical module 200.
An optical port of the optical module 200 is externally accessed to the optical fiber 101, and establishes bidirectional optical signal connection with the optical fiber 101; an electrical port of the optical module 200 is externally connected to the optical network terminal 100, and establishes bidirectional electrical signal connection with the optical network terminal 100; the optical module realizes the interconversion of optical signals and electric signals, thereby realizing the establishment of information connection between the optical fiber and the optical network terminal; specifically, the optical signal from the optical fiber is converted into an electrical signal by the optical module and then input to the optical network terminal 100, and the electrical signal from the optical network terminal 100 is converted into an optical signal by the optical module and input to the optical fiber.
The optical network terminal is provided with an optical module interface 102, which is used for accessing an optical module 200 and establishing bidirectional electric signal connection with the optical module 200; the optical network terminal is provided with a network cable interface 104, which is used for accessing the network cable 103 and establishing bidirectional electric signal connection with the network cable 103; the optical module 200 is connected to the network cable 103 through the optical network terminal 100, specifically, the optical network terminal transmits a signal from the optical module to the network cable and transmits the signal from the network cable to the optical module, and the optical network terminal serves as an upper computer of the optical module to monitor the operation of the optical module.
At this point, a bidirectional signal transmission channel is established between the remote server and the local information processing device through the optical fiber, the optical module, the optical network terminal and the network cable.
Common information processing apparatuses include routers, switches, electronic computers, and the like; the optical network terminal is an upper computer of the optical module, provides data signals for the optical module, and receives the data signals from the optical module, and the common upper computer of the optical module also comprises an optical line terminal and the like.
Fig. 2 is a schematic diagram of an optical network terminal structure. As shown in fig. 2, the optical network terminal 100 has a circuit board 105, and a cage 106 is disposed on a surface of the circuit board 105; an electric connector is arranged in the cage 106 and used for connecting an electric port of an optical module such as a golden finger; the cage 106 is provided with a heat sink 107, and the heat sink 107 has a projection such as a fin that increases a heat radiation area.
The optical module 200 is inserted into the optical network terminal, specifically, the electrical port of the optical module is inserted into the electrical connector inside the cage 106, and the optical port of the optical module is connected to the optical fiber 101.
The cage 106 is positioned on the circuit board, and the electrical connector on the circuit board is wrapped in the cage, so that the electrical connector is arranged in the cage; the optical module is inserted into the cage, held by the cage, and the heat generated by the optical module is conducted to the cage 106 and then diffused by the heat sink 107 on the cage.
Fig. 3 is a schematic structural diagram of an optical module 200 according to an embodiment of the present disclosure, and fig. 4 is an exploded structural diagram of the optical module 200 according to the embodiment of the present disclosure. As shown in fig. 3 and 4, an optical module 200 provided in an embodiment of the present application includes an upper housing 201, a lower housing 202, an unlocking handle 203, a circuit board 204, a light emitting module 205, and a light receiving module 206.
The upper shell 201 is covered on the lower shell 202 to form a wrapping cavity with two openings; the outer contour of the wrapping cavity is generally a square body, and specifically, the lower shell comprises a main plate and two side plates which are positioned at two sides of the main plate and are perpendicular to the main plate; the upper shell comprises a cover plate, and the cover plate covers two side plates of the upper shell to form a wrapping cavity; the upper shell can also comprise two side walls which are positioned at two sides of the cover plate and are perpendicular to the cover plate, and the two side walls are combined with the two side plates to realize that the upper shell covers the lower shell.
The two openings may be two openings (207, 208) located at the same end of the optical module, or two openings located at different ends of the optical module; one opening is an electric port 207, and a gold finger of the circuit board extends out of the electric port 207 and is inserted into an upper computer such as an optical network unit; the other opening is an optical port 208 for external optical fiber access to connect the optical transmitting assembly 205 and the optical receiving assembly 206 inside the optical module; optoelectronic devices such as circuit board 204, light emitting assembly 205 and light receiving assembly 206 are located in the package cavity.
The assembly mode of combining the upper shell and the lower shell is adopted, so that the circuit board 204, the light emitting assembly 205, the light receiving assembly 206 and other devices can be conveniently installed in the shell, and the outermost packaging protection shell of the optical module is formed by the upper shell and the lower shell; the upper shell and the lower shell are made of metal materials generally, so that electromagnetic shielding and heat dissipation are facilitated; generally, the shell of the optical module cannot be made into an integrated structure, so that when devices such as a circuit board and the like are assembled, the positioning component, the heat dissipation structure and the electromagnetic shielding structure cannot be installed, and the production automation is not facilitated.
The unlocking handle 203 is located on the outer wall of the wrapping cavity/lower shell 202 and used for realizing the fixed connection between the optical module and the upper computer or releasing the fixed connection between the optical module and the upper computer.
The unlocking handle 203 is provided with a clamping structure matched with the upper computer cage; the tail end of the unlocking handle is pulled to enable the unlocking handle to move relatively on the surface of the outer wall; the optical module is inserted into a cage of the upper computer, and the optical module is fixed in the cage of the upper computer through a clamping structure of the unlocking handle; by pulling the unlocking handle, the clamping structure of the unlocking handle moves along with the unlocking handle, so that the connection relation between the clamping structure and the upper computer is changed, the clamping relation between the optical module and the upper computer is relieved, and the optical module can be drawn out from the cage of the upper computer.
The optical transmitter 205 and the optical receiver 206 are respectively used for transmitting and receiving optical signals. The light emitting element 205 and the light receiving element 206 may be combined together to form an integrated light transmitting and receiving structure.
The circuit board 204 is provided with circuit traces, electronic components (such as capacitors, resistors, triodes, and MOS transistors), and chips (such as a laser driver chip, a limiting amplifier, a clock data recovery CDR, a power management chip, and a data processing chip DSP).
The circuit board 204 connects the electrical devices in the optical module together according to circuit design through circuit wiring to realize electrical functions such as power supply, electrical signal transmission, grounding and the like.
The circuit board 204 is generally a rigid circuit board, which can also realize a bearing effect due to its relatively hard material, for example, the rigid circuit board can stably bear a chip; the rigid circuit board may also provide a smooth load bearing when the light emitting assembly 205 and the light receiving assembly 206 are located on the circuit board; the hard circuit board can also be inserted into an electric connector in the upper computer cage, and specifically, a metal pin/golden finger is formed on the surface of the tail end of one side of the hard circuit board and is used for being connected with the electric connector; these are not easily implemented with flexible circuit boards.
A flexible circuit board is also used in a part of the optical module to supplement a rigid circuit board; the flexible circuit board is generally used in combination with a rigid circuit board, for example, the rigid circuit board may be connected to the optical transceiver device through the flexible circuit board.
In the examples of the present application. The light emitting assembly 205 is electrically connected to the circuit board 204, and the light emitting assembly 205 includes an EML laser 2051 therein. Fig. 5 is a block diagram of an EML laser 2051 according to an embodiment of the present application. As shown in fig. 5, an LD (Laser Diode), an EAM (Electro Absorption Modulator), a TEC (Thermoelectric Cooler), and the like are provided in the EML Laser 2051.
Fig. 6 is a schematic structural diagram of a circuit board according to an embodiment of the present application. Fig. 7 is a circuit diagram of a circuit board according to an embodiment of the present disclosure. As shown in fig. 5-7, in the embodiment of the present application, the circuit diagram includes an MCU2041, a first resistor 2042, an operational amplifier 2043, a second resistor 2044, a transistor 2045, a third resistor 2046, a first feedback circuit 2047, a second feedback circuit 2048, and an EML laser 2051. In particular, the method comprises the following steps of,
the MCU2041 is disposed on the circuit board 204 and configured to send a voltage signal. Specifically, since the MCU2041 has a VDAC (voltage-type digital-to-analog conversion output function), the input terminal of the MCU2041 is electrically connected to the upper computer through a gold finger. After receiving an instruction issued by the upper computer, the MCU2041 may convert the digital signal into an analog signal and send a corresponding voltage signal.
The first resistor 2042 is disposed on the circuit board 204, and an input end of the first resistor is electrically connected to an output end of the MCU 2041.
The operational amplifier 2043 is disposed on the circuit board 204, and a first input end of the operational amplifier is electrically connected to an output end of the first resistor 2042 for amplifying the voltage signal input by the first input end.
The operational amplifier 2043 is a circuit unit having a very high amplification factor. In an actual circuit, a certain functional module is usually formed together with a feedback network. It is an amplifier with special coupling circuit and feedback. The output signal may be the result of mathematical operations such as addition, subtraction or differentiation, integration, etc. of the input signal. In the embodiment of the present application, the operational amplifier 2043 amplifies the voltage signal input by the first input terminal, and the amplified voltage signal is output through the output terminal of the operational amplifier.
The second resistor 2044 is disposed on the circuit board 204, and has an input end electrically connected to the second input end of the operational amplifier 2043 and an output end grounded.
And the triode 2045 is arranged on the circuit board 204, the base electrode of the triode is electrically connected with the output end of the operational amplifier 2043, and the collector electrode of the triode is connected with the power supply and used for generating stable current according to the voltage output by the operational amplifier.
The transistor 2045 is a semiconductor device for controlling current, and is also called a bipolar transistor or a transistor. The function is to amplify the weak signal into an electric signal with larger amplitude value, and the electric signal is also used as a contactless switch. In this embodiment, a voltage signal output from the output terminal of the operational amplifier 2043 is input to the base of the triode 2045, and the collector is controlled by the base to be conducted with the emitter, so that the emitter outputs a current.
The third resistor 2046 is disposed on the circuit board 204, and an input end of the third resistor is electrically connected to an emitter of the transistor 2045.
The first feedback circuit 2047 is disposed on the circuit board 204, and has an input end electrically connected to the input end of the third resistor 2046 and an output end electrically connected to the input end of the second resistor 2044.
The first feedback circuit 2047 includes a fourth resistor R4. Specifically, the input terminal of the fourth resistor R4 is electrically connected to the input terminal of the third resistor 2046, and the output terminal thereof is electrically connected to the second input terminal of the operational amplifier 2043 (which is equivalent to "the output terminal is electrically connected to the input terminal of the second resistor 2044").
The second feedback circuit 2048 is disposed on the circuit board 204, and has an input end electrically connected to the output end of the third resistor 2046 and an output end electrically connected to the output end of the first resistor 2042.
The second feedback circuit 2048 includes a fifth resistor R5. Specifically, the input end of the fifth resistor R5 is electrically connected to the output end of the third resistor 2046, and the output end is electrically connected to the first input end of the operational amplifier 2043 (which is equivalent to "the output end is electrically connected to the output end of the first resistor 2042").
The current output from the emitter of the transistor 2045 partially flows to the first feedback circuit 2047, partially flows to the third resistor 2046, and partially flows to the second feedback circuit 2048. Since the resistances of the first feedback circuit 2047 and the second feedback circuit 2048 are large, the currents flowing to the first feedback circuit 2047 and the second feedback circuit 2048 are small and can be ignored. Therefore, the current output from the emitter of the transistor 2045 flows to the EML laser 2051 through the third resistor 2046.
The EML laser 2051 is disposed in the light emitting module 205, the input terminal LD + is electrically connected to the output terminal of the third resistor 2046, and the output terminal GND is grounded.
Since the current output by the emitter of the transistor 2045 flows through the third resistor 2046 to the EML laser 2051, the current flowing through the third resistor 2046 is equal to the current flowing through the EML laser 2051.
In this application, the working principle of the circuit is as follows:
the voltage of the input end of the third resistor is set to be V1, the voltage of the output end of the third resistor is set to be V2, the resistance ratio K1 of the fifth resistor to the first resistor and the resistance ratio K2 of the fourth resistor to the second resistor are set. Since the first input terminal and the second input terminal of the operational amplifier are "virtual short and virtual break", the voltages of the first input terminal and the second input terminal of the operational amplifier are equal, that is: vIN+＝VIN-＝VIN(1) (ii) a The currents of the first input terminal and the second input terminal of the operational amplifier are both 0, i.e. IIN+＝IIN-＝0(2)。
Since the currents of the first input terminal and the second input terminal of the operational amplifier are both 0, the first resistor 2042 is connected in series with the fifth resistor R5 in the second feedback circuit 2048, and the second resistor 2044 is connected in series with the fourth resistor R4 in the first feedback circuit 2047. Since the first resistor 2042 is connected in series with the fifth resistor R5, and the second resistor 2044 is connected in series with the fourth resistor R4, the current flowing through the first resistor 2042 is equal to the current flowing through the fifth resistor R5, and the current flowing through the second resistor 2044 is equal to the current flowing through the fourth resistor R4. Namely: (V)DAC-VIN+)/R1＝(VIN+-V2)/R5 (3) and (0-V)IN-)/R2＝(VIN--V1)/R4 (4)。
Obtained according to equation (3): v2 ═ V (1+ K1)IN-K1*VDAC (5)。
Obtained according to equation (4): v1 ═ V (1-K2)IN (6)。
Equation (6) minus equation (5), divided by third resistance 2046, yields: (V1-V2)/R3 ═ VIN*(K2-K1)/R3+K1*VDAC/R3 (7)。
As can be seen from equation (7), the current I flowing through the third resistor 2046 is equal to VIN*(K2-K1)/R3+K1*VDAC/R3 (8)。
Since the resistance ratio K1 of the fifth resistor R5 and the first resistor 2042 is equal to the resistance ratio K2 of the fourth resistor R4 and the second resistor 2044, equation (8) may be changed to I-K1 × VDAC/R3 (9)。
According to the formula (9), the current I flowing through the third resistor 2046 is only equal to the voltage V output by the fifth resistor R5, the first resistor 2042, the third resistor 2046 and the MCU2041DACHowever, the resistances of the fifth resistor R5, the first resistor 2042, and the third resistor 2046 are limited, so that the adjustable stable current can be obtained.
Since the fourth resistor R4 and the fifth resistor R5 have relatively large resistance values, the current flowing through the first feedback circuit 2047 and the second feedback circuit 2048 is ignored, and the current flowing through the EML laser 2051 and the current flowing through the third resistor 2046 are approximately equal, that is, the current flowing through the EML laser 2051 is I.
Fig. 8 is another circuit diagram of a circuit board according to an embodiment of the present disclosure. Referring to fig. 5, 6 and 8, in the embodiment of the present application, the circuit diagram includes an MCU2041, a first resistor 2042, an operational amplifier 2043, a second resistor 2044, a MOS transistor 2045, a third resistor 2046, a first feedback circuit 2047, a second feedback circuit 2048 and an EML laser 2051.
The MOS 2045 is disposed on the circuit board 204, and has a gate electrically connected to the output terminal of the operational amplifier 2043 and a drain connected to the power supply, and is configured to generate a stable current according to the voltage output by the operational amplifier 2043.
The third resistor 2044 is disposed on the circuit board 204, and an input end of the third resistor is electrically connected to the source of the MOS transistor 2045.
In the embodiment of the present application, except for the MOS transistor 2045, the remaining structures are the same, and the principle is the same, which is not described herein again.
An optical module includes a circuit board and a light emitting assembly electrically connected to the circuit board. The light emitting assembly includes an EML laser. The circuit board is provided with an MCU, a first resistor, an operational amplifier, a second resistor, a triode, a first feedback circuit and a second feedback circuit. And the input end of the first resistor is electrically connected with the output end of the MCU. And the first input end of the operational amplifier is electrically connected with the output end of the first resistor. And the input end of the second resistor is electrically connected with the second input end of the operational amplifier, and the output end of the second resistor is grounded. And the base electrode of the triode is electrically connected with the output end of the operational amplifier, and the collector electrode of the triode is connected with the power supply and used for emitting stable current according to the voltage output by the operational amplifier. And the input end of the third resistor is electrically connected with the emitting electrode of the triode, and the output end of the third resistor is electrically connected with the EML laser. And the input end of the first feedback circuit is electrically connected with the input end of the third resistor, and the output end of the first feedback circuit is electrically connected with the input end of the second resistor. And the input end of the second feedback circuit is electrically connected with the output end of the third resistor, and the output end of the second feedback circuit is electrically connected with the output end of the first resistor. The MCU sends a voltage signal, after the voltage signal is divided by the first resistor, only part of the voltage signal is input into the first input end of the operational amplifier, after the voltage signal is amplified by the operational amplifier, the voltage output by the operational amplifier is input into the base electrode of the triode, the collector electrode and the emitter electrode of the triode are controlled to be conducted, so that the emitter electrode of the triode sends current, part of the current is input into the second input end of the operational amplifier through the first feedback circuit, and part of the current flows to the EML laser through the third resistor. The current flowing through the third resistor flows partly to the EML laser and partly to the second feedback circuit. Because the resistance values of the first feedback circuit and the second feedback circuit are large, the current flowing through the first feedback circuit and the second feedback circuit is ignored, and the current flowing through the fifth resistor is equal to the current flowing through the EML laser. The current flowing through the fifth resistor is obtained through calculation of the first feedback circuit and the second feedback circuit and is only related to the voltage emitted by the MCU and the resistance values of the resistors, so that the current flowing through the fifth resistor is adjustable stable current, namely the current flowing through the EML laser is adjustable stable current. According to the EML laser, the MCU, the resistors, the operational amplifier, the triode and the two feedback circuits are arranged, so that the adjustable stable current only related to the voltage and each resistance value sent by the MCU can be output, and the adjustable stable current is provided for the EML laser; because the components are arranged on the circuit board, only a small amount of PCB space is occupied, and the PCB space is not limited. In addition, in the application, a stable power supply can be formed by only a few devices without a special power supply chip, so that the cost of the optical module is effectively reduced.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.
Claims (5)
1. A light module, comprising:
a circuit board;
the light emitting assembly comprises an EML laser and is electrically connected with the circuit board;
the circuit board is provided with:
the MCU is used for sending a voltage signal;
the input end of the first resistor is electrically connected with the output end of the MCU;
the first input end of the operational amplifier is electrically connected with the output end of the first resistor and is used for amplifying the voltage signal input by the first input end;
the input end of the second resistor is electrically connected with the second input end of the operational amplifier, and the output end of the second resistor is grounded;
the base electrode of the triode is electrically connected with the output end of the operational amplifier, and the collector electrode of the triode is connected with the power supply and used for sending out stable current according to the voltage output by the operational amplifier;
the input end of the third resistor is electrically connected with the emitting electrode of the triode, and the output end of the third resistor is electrically connected with the EML laser;
the input end of the first feedback circuit is electrically connected with the input end of the third resistor, and the output end of the first feedback circuit is electrically connected with the input end of the second resistor;
and the input end of the second feedback circuit is electrically connected with the output end of the third resistor, and the output end of the second feedback circuit is electrically connected with the output end of the first resistor.
2. The light module of claim 1, wherein the first feedback circuit comprises a fifth resistor.
3. The light module of claim 2, wherein the second feedback circuit comprises a sixth resistor.
4. The optical module according to claim 3, wherein a resistance ratio of the sixth resistor to the first resistor is equal to a resistance ratio of the fifth resistor to the second resistor.
5. A light module, comprising:
a circuit board;
the light emitting assembly comprises an EML laser and is electrically connected with the circuit board;
the circuit board is provided with:
the MCU is used for sending a voltage signal;
the input end of the first resistor is electrically connected with the output end of the MCU;
the first input end of the operational amplifier is electrically connected with the output end of the first resistor and is used for amplifying the voltage signal input by the first input end;
the input end of the second resistor is electrically connected with the second input end of the operational amplifier, and the output end of the second resistor is grounded;
the grid electrode of the MOS tube is electrically connected with the output end of the operational amplifier, and the drain electrode of the MOS tube is connected with the power supply and used for sending out stable current according to the voltage output by the operational amplifier;
the input end of the third resistor is electrically connected with the source electrode of the MOS tube, and the output end of the third resistor is electrically connected with the EML laser;
the input end of the first feedback circuit is electrically connected with the input end of the third resistor, and the output end of the first feedback circuit is electrically connected with the input end of the second resistor;
and the input end of the second feedback circuit is electrically connected with the output end of the third resistor, and the output end of the second feedback circuit is electrically connected with the output end of the first resistor.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202021135040.4U CN212543787U (en) | 2020-06-18 | 2020-06-18 | Optical module |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021135040.4U CN212543787U (en) | 2020-06-18 | 2020-06-18 | Optical module |
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| CN212543787U true CN212543787U (en) | 2021-02-12 |
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