CN116938338A

CN116938338A - Laser signal transmission system

Info

Publication number: CN116938338A
Application number: CN202310884870.9A
Authority: CN
Inventors: 樊小明; 樊家玮
Original assignee: Shenzhen Zhiyong Electronic Co ltd
Current assignee: Shenzhen Zhiyong Electronic Co ltd
Priority date: 2023-07-18
Filing date: 2023-07-18
Publication date: 2023-10-24

Abstract

The application discloses a laser signal transmission system which comprises an electric signal generation module, an electro-optical conversion module, a photoelectric conversion module, a signal amplification module and a control module. The electric signal generation module outputs a first current based on the input voltage, and outputs a first voltage that exhibits a proportional relationship with a difference between the first current and a threshold current of the electro-optical conversion module. And stopping the operation of the electro-optical conversion module when the current flowing through the electro-optical conversion module is smaller than the threshold current. The electro-optical conversion module outputs an optical signal corresponding to the first current. The photoelectric conversion module receives an optical signal from the analog optical fiber and outputs a voltage corresponding to the optical signal. The signal amplifying module amplifies the voltage corresponding to the optical signal and outputs a second voltage. The control module adjusts the amplification factor of the signal amplification module based on a first ratio of the first voltage to the second voltage. By the mode, when the electro-optical conversion coefficient is changed due to temperature drift, the change of the electro-optical conversion coefficient can be compensated, so that the transmission precision is improved.

Description

Laser signal transmission system

Technical Field

The application relates to the technical field of signal transmission, in particular to a laser signal transmission system.

Background

Currently, fiber optic signal transmission systems are typically constructed of three parts. These three parts include a transmitter that converts an electrical signal into an optical signal, an analog fiber that connects the transmitter and the receiver to transmit the optical signal, and a receiver that converts the optical signal into an electrical signal. The analog optical fiber is used for transmitting signals, and has the advantages of strong anti-interference performance and capability of bearing very high voltage.

Among these, there is an electro-optical conversion module, such as a laser diode, in the transmitter that will convert an electrical signal into an optical signal. In the process of realizing the optical fiber transmission analog signal, the existence of temperature drift of the electro-optical conversion coefficient of the electro-optical conversion module can lead to poor transmission precision.

Disclosure of Invention

The application aims to provide a laser signal transmission system which can compensate the change of an electro-optical conversion coefficient when the electro-optical conversion coefficient is changed due to temperature drift, thereby improving transmission precision.

To achieve the above object, in a first aspect, the present application provides a laser signal transmission system, comprising:

the electric signal generation module is respectively connected with the electro-optical conversion module and the input voltage;

the electric signal generation module is used for outputting a first current based on the input voltage and outputting a first voltage which has a proportional relation with a difference value between the first current and a threshold current of the electro-optical conversion module, wherein when the current flowing through the electro-optical conversion module is smaller than the threshold current, the electro-optical conversion module stops working;

The electro-optical conversion module is used for outputting an optical signal corresponding to the first current, wherein the optical signal is transmitted through an analog optical fiber;

a photoelectric conversion module for receiving the optical signal from the analog optical fiber and outputting a voltage corresponding to the optical signal;

the signal amplification module is connected with the photoelectric conversion module and is used for amplifying the voltage corresponding to the optical signal and outputting a second voltage;

the control module is respectively connected with the electric signal generation module and the signal amplification module, and is used for adjusting the amplification factor of the signal amplification module based on the first ratio of the first voltage to the second voltage.

In an optional manner, the laser signal transmission system further includes a waveform generation module, a first comparison module, and a second comparison module;

the waveform generation module is respectively connected with the control module, the first comparison module and the second comparison module, the first comparison module is also respectively connected with the electric signal generation module and the control module, and the second comparison module is also respectively connected with the signal amplification module and the control module;

The control module is used for outputting pulse signals to the waveform generation module;

the waveform generation module is used for outputting a first waveform based on the pulse signal, wherein the first waveform comprises a sawtooth wave or a triangular wave;

the first comparison module is used for outputting a first comparison pulse to the control module based on a comparison result of the first voltage and the first waveform;

the second comparison module is used for outputting a second comparison pulse to the control module based on a comparison result of the second voltage and the first waveform;

the control module is further configured to determine the first ratio based on a ratio of a pulse width of the first comparison pulse to a pulse width of the second comparison pulse.

In an alternative manner, the waveform generation module includes a first waveform generator, a second waveform generator, a first digital fiber transmitter, and a first digital fiber receiver;

the control module is respectively connected with the second waveform generator and the first digital optical fiber transmitter, the first digital optical fiber transmitter is connected with the first digital optical fiber receiver through digital optical fibers, and the first digital optical fiber receiver is also connected with the first waveform generator;

The control module is used for outputting a pulse signal to the second waveform generator and the first digital optical fiber transmitter, and the pulse signal is input to the first waveform generator through the first digital optical fiber transmitter and the first digital optical fiber receiver;

the first waveform generator is connected with the first comparison module and is used for inputting the first waveform to the first comparison module based on the pulse signal;

the second waveform generator is connected with the second comparison module and is used for inputting the first waveform to the second comparison module based on the pulse signal.

In an alternative manner, the control module is further configured to:

determining the second voltage as: v2=k (ILD 1-Ith), where V2 is the second voltage, K is the electro-optical conversion coefficient of the electro-optical conversion module, ILD1 is the first current, and Ith is the threshold current.

In an alternative manner, the electrical signal generating module includes a first amplifier and a power transistor;

the first input end of the first amplifier is connected with the input voltage, the second input end of the first amplifier is connected with the emitter of the power triode, the output end of the first amplifier is connected with the base electrode of the power triode, the collector electrode of the power triode is connected with the first end of the electro-optical conversion module, and the second end of the electro-optical conversion module is connected with a positive voltage source;

The first amplifier is used for amplifying the input voltage and inputting the amplified input voltage to the power triode so as to conduct the power triode and generate the first current.

In an alternative manner, the electric signal generating module further comprises a resistor, a first subtracter and a second subtracter;

the first end of the resistor is respectively connected with the second input end of the first amplifier and the first input end of the first subtracter, the second end of the resistor is respectively connected with a negative voltage source and the second input end of the first subtracter, the output end of the first subtracter is connected with the first input end of the second subtracter, the second input end of the second subtracter inputs a reference voltage, and the output end of the second subtracter outputs the first voltage, wherein the reference voltage is obtained by multiplying the threshold current by the resistance value of the resistor.

In an alternative manner, the first voltage is: v1=r1 (ILD 1-Ith), where V1 is the first voltage and R1 is the resistance value of the resistor.

In an alternative manner, the resistance value of the resistor is configured to be equal to a reference electro-optic conversion coefficient of the electro-optic conversion module;

The control module is further configured to:

determining a first reference ratio of the first voltage to the second voltage to be 1;

if the first reference ratio is equal to the first ratio, keeping the amplification factor of the signal amplification module unchanged;

if the first reference ratio is larger than the first ratio, reducing the amplification factor of the signal amplification module;

and if the first reference ratio is smaller than the first ratio, increasing the amplification factor of the signal amplification module.

In an alternative manner, the control module is further configured to:

determining a reference electro-optic conversion coefficient of the electro-optic conversion module;

determining a second reference ratio of the first voltage to the second voltage based on the reference voltage conversion coefficient;

if the second reference ratio is equal to the first ratio, keeping the amplification factor of the signal amplification module unchanged;

if the second reference ratio is larger than the first ratio, reducing the amplification factor of the signal amplification module;

and if the second reference ratio is smaller than the first ratio, increasing the amplification factor of the signal amplification module.

In an alternative, the electro-optic conversion module comprises a laser diode,

The first end of the laser diode is connected with a positive power supply, and the second end of the laser diode is connected with the electric signal generating module.

In an alternative, the photoelectric conversion module includes a photodiode;

the first end of the photodiode is connected with a positive power supply, and the second end of the photodiode is connected with the signal amplifying module;

the photodiode is used for receiving the optical signal from the analog optical fiber and outputting a voltage corresponding to the optical signal to the signal amplifying module.

In an optional manner, the laser signal transmission system further comprises a subtracter, and the subtracter is respectively connected with the signal amplifying module and the control module;

the control module is further configured to obtain a static working current of the electro-optical conversion module, and output a third voltage corresponding to the static working current to the subtractor, where when the input voltage is 0, a current flowing through the electro-optical conversion module is the static working current;

the subtractor is configured to generate an output voltage based on a difference between the second voltage and the third voltage.

The beneficial effects of the application are as follows: the laser signal transmission system provided by the application comprises an electric signal generation module, an electro-optical conversion module, a photoelectric conversion module, a signal amplification module and a control module. The electric signal generating module is respectively connected with the electro-optical conversion module and the input voltage. The signal amplifying module is connected with the photoelectric conversion module. The control module is respectively connected with the electric signal generating module and the signal amplifying module. The electric signal generation module is used for outputting a first current based on the input voltage and outputting a first voltage which has a proportional relation with the difference value between the first current and the threshold current of the electro-optical conversion module. When the current flowing through the electro-optical conversion module is smaller than the threshold current, the electro-optical conversion module stops working. The electro-optical conversion module is used for outputting an optical signal corresponding to the first current. Wherein the optical signal is transmitted through an analog optical fiber. The photoelectric conversion module is used for receiving the optical signal from the analog optical fiber and outputting a voltage corresponding to the optical signal. The signal amplifying module is used for amplifying the voltage corresponding to the optical signal and outputting a second voltage. The control module is used for adjusting the amplification factor of the signal amplification module based on a first ratio of the first voltage to the second voltage. By the mode, when the electro-optical conversion coefficient is changed due to temperature drift, the change of the electro-optical conversion coefficient can be compensated by adjusting the amplification factor of the signal amplification module, so that the transmission precision is improved.

Drawings

One or more embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like references indicate similar elements, and in which the figures of the drawings are not to be taken in a limiting sense, unless otherwise indicated.

Fig. 1 is a schematic structural diagram of a laser signal transmission system according to a first embodiment of the present application;

fig. 2 is a schematic structural diagram of a laser signal transmission system according to a second embodiment of the present application;

fig. 3 is a schematic diagram of waveforms of signals in a laser signal transmission system according to a first embodiment of the present application;

fig. 4 is a schematic diagram of waveforms of signals in a laser signal transmission system according to a second embodiment of the present application;

FIG. 5 is a flowchart of a method performed by a control module according to a first embodiment of the present application;

FIG. 6 is a schematic diagram of a first current and a second voltage according to a first embodiment of the present application;

fig. 7 is a schematic circuit diagram of a laser signal transmission system according to a first embodiment of the present application;

FIG. 8 is a flowchart of a method performed by a control module according to a second embodiment of the present application;

FIG. 9 is a flowchart of a method performed by a control module according to a third embodiment of the present application;

Fig. 10 is a schematic circuit diagram of a laser signal transmission system according to a second embodiment of the present application.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present application more apparent, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments of the present application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a laser signal transmission system according to an embodiment of the application. As shown in fig. 1, the laser signal transmission system 100 includes an electrical signal generation module 10, an electro-optical conversion module 20, a photoelectric conversion module 30, a signal amplification module 40, and a control module 50.

The electric signal generating module 10 is connected to the electro-optical conversion module 20 and the input voltage VIN, respectively. The signal amplification module 40 is connected to the photoelectric conversion module 30. The control module 50 is connected to the electric signal generating module 10 and the signal amplifying module 40, respectively. Specifically, the first end of the electric signal generating module 10 is connected to the input voltage VIN, the second end of the electric signal generating module 10 is connected to the first end of the electro-optical conversion module 20, the third end of the electric signal generating module 10 is connected to the first end of the control module 50, the first end of the photoelectric conversion module 30 is connected to the first end of the signal amplifying module 40, the second end of the signal amplifying module 40 is connected to the second end of the control module 50, and the third end of the control module 50 is connected to the third end of the signal amplifying module 40.

In this embodiment, the electrical signal generation module 10 outputs the first current based on the input voltage VIN. In some embodiments, the electrical signal generation module 10 is specifically capable of linearly converting the input voltage VIN to a first current, thereby implementing a voltage-controlled current source. The first current is input to the electro-optical conversion module 20. The electro-optical conversion module 10 outputs an optical signal corresponding to the first current. Wherein the optical signal corresponds to the first current means that the optical signal has a proportional relation, e.g. a direct proportional relation, with the first current. The optical signal is then transmitted through an analog optical fiber. The photoelectric conversion module 30 receives an optical signal from the analog optical fiber 200 and outputs a voltage corresponding to the optical signal. The voltage corresponding to the optical signal means a voltage having a proportional relationship with the optical signal, for example, a proportional relationship. The voltage is input to the signal amplification module 40. The signal amplifying module 40 amplifies the voltage corresponding to the optical signal and outputs a second voltage (denoted as a second voltage V2) to the control module 50. It can be understood that, since the signal amplifying module 40 inputs a voltage corresponding to the optical signal, the amplified second voltage V2 also has a corresponding relationship with the optical signal.

Meanwhile, the electric signal generation module 10 also outputs a first voltage (denoted as a first voltage V1) exhibiting a proportional relationship with a difference between the first current (denoted as a first current ILD 1) and a threshold current (denoted as a threshold current Ith) of the electro-optical conversion module 20. I.e., V1 and (ILD 1-Ith) exhibit a proportional relationship. Wherein, when the current flowing through the electro-optical conversion module 20 is smaller than the threshold current, the electro-optical conversion module 20 stops working. In other words, the threshold current is the minimum operation current of the electro-optical conversion module 20, and the electro-optical conversion module 20 outputs the optical signal only when the current flowing through the electro-optical conversion module 20 is greater than or equal to the threshold current. Then, the first voltage is also input to the control module 50.

Then, the control module 50 adjusts the amplification factor of the signal amplifying module 40 based on the first ratio of the first voltage V1 and the second voltage V2. The first ratio is a ratio of the first voltage V1 to the second voltage V2 obtained in real time. In this embodiment, as can be seen from the above description, the optical signal has a proportional relationship with the first current and the second voltage, respectively, so the first current and the second voltage also have a proportional relationship. Further, the threshold current of the electro-optical conversion module 20 is a constant characteristic, so that the difference between the second voltage V2 and the first current ILD1 and the threshold current Ith can be obtained to show a proportional relationship. I.e., V2 and (ILD 1-Ith) exhibit a proportional relationship. And since this proportional relationship is related to the optical signal, it is necessarily related to the electro-optical conversion coefficient of the electro-optical conversion module 20. And then the ratio of the first voltage V1 to the second voltage V2 and the corresponding relation between the electro-optical conversion coefficient can be obtained by combining the V1 and (ILD 1-Ith) to show a positive proportion relation. Then, when the electro-optical conversion coefficient is changed due to temperature drift, the change condition of the electro-optical conversion coefficient can be determined through the ratio of the first voltage V1 to the second voltage V2, and the amplification factor of the signal amplification module is correspondingly adjusted, so that the change of the electro-optical conversion coefficient can be compensated, and the transmission precision is improved.

In some embodiments, control module 50 may be a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), a single-chip, ARM (Acorn RISC Machine) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof. Also, the control module 50 may be any conventional processor, controller, microcontroller, or state machine. Control module 50 may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP, and/or any other such configuration.

In addition, it should be noted that, in the embodiment of the present application, the first voltage V1 and the second voltage V2 include signals in the full frequency band.

In one embodiment, as shown in fig. 2, the laser signal transmission system 100 further includes a waveform generation module 60, a first comparison module 70, and a second comparison module 80.

The waveform generating module 60 is respectively connected to the control module 50, the first comparing module 70 and the second comparing module 80, the first comparing module 70 is respectively connected to the electric signal generating module 10 and the control module 50, and the second comparing module 80 is respectively connected to the signal amplifying module 40 and the control module 50. Specifically, the first end of the waveform generating module 60 is connected to the fourth end of the controller 50, the second end of the waveform generating module 60 is connected to the first end of the first comparing module 70, the third end of the waveform generating module 60 is connected to the first end of the second comparing module 80, the second end of the second comparing module 80 is connected to the second end of the signal amplifying module 40, the third end of the second comparing module 80 is connected to the second end of the control module 50, the second end of the first comparing module 70 is connected to the third end of the signal generating module 10, and the third end of the first comparing module 70 is connected to the first end of the control module 50.

In this embodiment, the control module 50 outputs a pulse signal to the waveform generation module 60. The waveform generation module 60 outputs a first waveform based on the pulse signal. Wherein the first waveform comprises a sawtooth or triangular wave. The first comparing module 70 is configured to output a first comparing pulse to the control module 50 based on a comparison result of the first voltage and the first waveform. The second comparing module 80 is configured to output a second comparing pulse to the control module 50 based on a comparison result of the second voltage and the first waveform. The control module 50 is further configured to determine the first ratio value based on a ratio of a pulse width of the first comparison pulse to a pulse width of the second comparison pulse.

Hereinafter, the first waveform will be described by taking a sawtooth waveform as an example.

Referring to fig. 3, fig. 3 is a schematic diagram illustrating a manner of obtaining a sawtooth wave based on a pulse signal. As shown in fig. 3, a curve L11 is a pulse signal; curve L12 is a sawtooth wave.

Specifically, at time t0, a rising edge of the pulse signal comes, and the voltage output from the waveform generation module 60 is gradually increased by the curve L12. Until the time t1, the next rising edge of the pulse signal comes, the voltage output by the waveform generation module 60, which is available from the curve L12, instantaneously decreases to a minimum value, and then starts increasing again. As the rising edge of the pulse signal continues, the voltage output by the waveform generation module 60 repeats the above-mentioned changing process, and finally a sawtooth wave is formed.

Referring to fig. 4, fig. 4 is a schematic diagram illustrating a manner of determining a first comparison pulse and a second comparison pulse based on a first waveform. Wherein, the curve L21 is a first waveform; curve L22 is the first comparison pulse; curve L23 is the second comparison pulse. Moreover, since the first voltage V1 and the second voltage V2 include signals having full frequency bands, the first voltage V1 and the second voltage V2 are not signals that remain unchanged. At this time, if the ratio of the first voltage V1 to the second voltage V2 is directly used to adjust the amplification factor of the signal amplifying module, the obtained comparison value has poor accuracy, which results in abnormal adjustment of the amplification factor.

Further, the first voltage V1 and the second voltage V2 are simultaneously compared with the first waveform. The first comparison pulse and the second comparison pulse can be obtained according to the comparison result. Specifically, when the first voltage V1 is greater than the voltage corresponding to the first waveform, the first comparison module 70 outputs a high level; when the first voltage V1 is smaller than the voltage corresponding to the first waveform, the first comparison module 70 outputs a low level. As the voltage of the first waveform changes, the first comparison module 70 alternately outputs a high and low level, i.e., a first comparison pulse. Similarly, when the second voltage V2 is greater than the voltage corresponding to the first waveform, the second comparing module 80 outputs a high level; when the second voltage V2 is smaller than the voltage corresponding to the first waveform, the second comparing module 80 outputs a low level. As the voltage of the first waveform changes, the second comparing module 80 alternately outputs a high and low level, i.e., a second comparing pulse.

The control module 50 is then able to determine the pulse width of the first comparison pulse and the pulse width of the second comparison pulse. As shown in fig. 4, the high-level duration T1 of the first comparison pulse is used as the pulse width of the first comparison pulse, and the high-level duration T2 of the second comparison pulse is also used as the pulse width of the first comparison pulse. The control module 50 uses the ratio of T1 to T2 as the ratio of the first voltage V1 to the second voltage V2, which can have higher accuracy to ensure that the amplification factor of the signal amplifying module 40 is accurately adjusted. In addition, in other embodiments, the low-level duration of the first comparison pulse may be used as the pulse width of the first comparison pulse, and the low-level duration of the second comparison pulse may be used as the pulse width of the first comparison pulse, which is within the range of those skilled in the art and will not be described herein.

The embodiment of the application also provides a mode for determining the first voltage V1 and the second voltage V2 respectively.

Specifically, in one embodiment, as shown in fig. 5, the control module 50 is further configured to perform the following steps:

step 501: determining the second voltage as: v2=k (ILD 1-Ith).

Wherein V2 is a second voltage. K is the electro-optical conversion coefficient of the electro-optical conversion module 20. ILD1 is the first current. Ith is the threshold current. The threshold current Ith is related to the characteristics of the electro-optical conversion module 20.

Referring to fig. 5 and fig. 6 together, one way of the first current and the first voltage is illustrated in fig. 6. As shown in fig. 6, the abscissa is the first current ILD1; the ordinate is the second voltage V2.

The electro-optical conversion module 20 does not output an optical signal until the first current ILD1 increases to be equal to the threshold current Ith, in which case the second voltage V2 remains at 0. After the first current ILD1 increases to be greater than the threshold current Ith, the second voltage V2 increases as the first current ILD1 increases. And, the first current ILD1 and the second voltage V2 show a proportional relationship. For example, if the waveform of the first current ILD1 is shown by the curve L31, the waveform of the second voltage V2 is shown by the curve L32, and it can be seen that the waveform of the first current ILD1 and the waveform of the second voltage V2 have a direct proportional relationship, and the ratio is the electro-optical conversion coefficient K of the electro-optical conversion module 10. V2 = K (ILD 1-Ith) is available in aggregate. To this end, a process of determining the second voltage V2 is implemented.

Referring to fig. 7, fig. 7 is a circuit structure of a laser signal transmission system.

In one embodiment, as shown in fig. 7, the electrical signal generating module 10 includes a first amplifier U1 and a power transistor Q1.

The first input end of the first amplifier U1 is connected to the input voltage VIN, the second input end of the first amplifier U1 is connected to the emitter of the power triode Q1, the output end of the first amplifier U1 is connected to the base of the power triode Q1, the collector of the power triode Q1 is connected to the first end of the electro-optical conversion module 20, and the second end of the electro-optical conversion module 20 is connected to the positive voltage source v+. The first input terminal of the first amplifier U1 is a non-inverting input terminal, and the second input terminal is an inverting input terminal.

The first amplifier U1 is configured to amplify the input voltage VIN and input the amplified input voltage VIN to the power transistor Q1, so that the power transistor Q1 is turned on and generates a first current.

In another embodiment, the electrical signal generating module 10 further includes a resistor R1, a first subtractor U3, and a second subtractor U4.

The first end of the resistor R1 is connected to the second input end of the first amplifier U1 and the first input end of the first subtractor U3, the second end of the resistor R1 is connected to the negative voltage source V-and the second input end of the first subtractor U3, the output end of the first subtractor U3 is connected to the first input end of the second subtractor U4, the second input end of the second subtractor U4 inputs the reference voltage Vth, and the output end of the second subtractor U4 outputs the first voltage. The first input end of the first subtracter U3 (and the second subtracter U4) is a non-inverting input end, and the second input end is an inverting input end. The reference voltage Vth is obtained by multiplying a threshold current by the resistance of the resistor, i.e., vth=ith×r1.

In one embodiment, the waveform generation module 60 includes a first waveform generator 61, a second waveform generator 62, a first digital fiber transmitter 63, and a first digital fiber receiver 64.

The control module 50 is connected to the second waveform generator 62 and the first digital fiber transmitter 64, respectively. The first digital fiber transmitter 64 is connected to the first digital fiber receiver 63 by a digital fiber 300. The first digital fiber optic receiver 63 is also connected to a first waveform generator 61. The first waveform generator 61 is connected to a first comparison module 70. The second waveform generator 62 is connected to a second comparison module 80. Specifically, the fourth end of the control module 50 is connected to the first end of the second waveform generator 62 and the first end of the first digital optical fiber transmitter 64, the second end of the second waveform generator 62 is connected to the first end of the second comparison module 80, the second end of the first digital optical fiber transmitter 64 is connected to the first end of the first digital optical fiber receiver 63 through the digital optical fiber 300, the second end of the first digital optical fiber receiver 63 is connected to the first end of the first waveform generator 61, and the second end of the first waveform generator 61 is connected to the first end of the first comparison module 70.

Specifically, the control module 50 is configured to output a pulse signal to the second waveform generator 62 and the first digital fiber transmitter 64. And the pulse signal is input to the first waveform generator 61 through the first digital optical fiber transmitter 64 and the first digital optical fiber receiver 63. The first waveform generator 61 is for inputting a first waveform to the first comparing module 70 based on the pulse signal. The second waveform generator 62 is used for inputting the first waveform to the second comparison module 80 based on the pulse signal.

The first digital fiber optic transmitter 64 is a device that converts digital electrical signals into optical signals. It typically comprises a light source such as a laser diode or LED that is controlled by a modulation circuit and transmitted to a receiving end using a digital optical fiber 300. The first digital fiber optic receiver 63 is a device for converting optical signals into digital electrical signals. It typically includes an optical-to-electrical converter that converts an optical signal into an electrical signal, amplifies and filters it, and then converts it into a digital signal using an analog-to-digital converter.

Further, in this embodiment, the voltages at the two input terminals of the first amplifier U1 are eventually equal based on the characteristics of the virtual short and the virtual break of the first amplifier U1. Therefore, the input voltage VIN is equal to the voltage at the first terminal of the resistor R1. And the voltage at the second terminal of the resistor R1 is the voltage supplied by the negative power supply V-. The first current ILD1 = (VIN-V-)/R1, where R1 is the resistance of the resistor R1.

When the input voltage VIN is 0, the first current ild1= -V-/r1. The first current ILD1 at this time Is denoted as the static operation current Is of the electro-optical conversion module 20. Referring back to fig. 6, the quiescent operating current Is illustrated in fig. 6. By providing the static operation current Is for the electro-optical conversion module 20, when the input voltage VIN Is input to the signal transmission system, the operation current of the electro-optical conversion module 20 can fluctuate in a linear section of the static operation current Is, so that the first voltage V2 also changes linearly. In this way, the first voltage V2 does not generate signal distortion.

In an embodiment, referring to fig. 7, the first comparing module 70 includes a first comparator U5, and the second comparing module 80 includes a second comparator U6.

The non-inverting input terminal of the first comparator U5 is connected to the output terminal of the second subtractor U4, the inverting input terminal of the first comparator U5 is connected to the second terminal of the first waveform generator 61, and the output terminal of the first comparator U5 is connected to the first terminal of the control module 50. The non-inverting input of the second comparator U6 is connected to the output of the second amplifier U2, the inverting input of the second comparator U6 is connected to the second end of the second waveform generator 62, and the output of the second comparator U6 is connected to the second end of the control module 50.

In one embodiment, the electro-optic conversion module 20 includes a laser diode LD1.

Wherein, the first end of the laser diode LD1 is connected with the positive power supply V+, and the second end of the laser diode LD1 is connected with the electric signal generating module connection 10.

Specifically, the laser diode LD1 is a semiconductor laser, also called LD (Laser Diode). It uses semiconductor materials to generate and amplify a laser beam. The laser diode LD1 operates on the principle that stimulated radiation is generated and amplified into laser light (i.e., an output optical signal) by injecting a current into a semiconductor material.

In an embodiment, the photoelectric conversion module 30 includes a photodiode PD1. The first terminal of the photodiode PD1 is connected to the positive power supply v+ and the input terminal of the second amplifier U2 is connected to the signal amplifying module 40.

Specifically, the photodiode PD1 is configured to receive an optical signal from an analog optical fiber and output a voltage corresponding to the optical signal to the signal amplification module 40.

The principle of the circuit configuration shown in fig. 7 will be explained again.

When the input voltage VIN is input to the laser signal transmission system 100, the signal output by the first amplifier U1 turns on the power transistor Q1 and generates the first current ILD1. The first current ILD1 flows through the laser diode LD1 and the resistor R1. The laser diode LD1 outputs an optical signal. The optical signal is then transmitted through an analog optical fiber. The photodiode PD1 receives an optical signal from the analog optical fiber 200 and outputs a voltage corresponding to the optical signal. The voltage is input to the second amplifier U2. The second amplifier U2 amplifies a voltage corresponding to the optical signal and outputs a second voltage V2 to the control module 50. At this time, the second voltage v2=k (ILD 1-Ith) (1).

At the same time, a first current ILD1 flows through the resistor R1 to generate a voltage ILD1×r1 across the resistor R1. Since the signal output by the output terminal of the first subtractor U3 is the difference between the voltages input by the non-inverting input terminal and the inverting input terminal of the first subtractor U3, that is, the voltage ILD1 x R1 across the resistor R1. The voltage ILD1 x R1 is input to the second subtractor U4. The output of the second subtractor U4 is ILD1 x R1-Vth. Since vth=ith×r1, ILD1×r1-vth=ild1×r1-ith×r1=r1× (ILD 1-Ith). The output of the second subtractor U4 outputs a first voltage V1, which is v1=r1 (ILD 1-Ith) (2).

Then, combining equation (1) with equation (2) can be obtained: v1/v2=r1/K (3). Therefore, when the resistance value of the resistor R1 has been determined, V1/V2 has a correspondence with K. Based on this, when the electro-optical conversion coefficient K changes due to temperature drift, the control module 50 can determine the change condition of the electro-optical conversion coefficient K through the ratio of the first voltage V1 to the second voltage V2, and further correspondingly adjust the amplification factor of the second amplifier U2, so as to compensate the change of the electro-optical conversion coefficient K, thereby improving the transmission precision.

Further, based on the formula (3), the embodiment of the present application can also determine the ratio of the first voltage V1 to the second voltage V2 when the electro-optical conversion coefficient K is not affected by the temperature drift. The ratio is taken as a reference ratio, the ratio of the first voltage V1 to the second voltage V2 is obtained in the laser signal transmission process, the ratio is compared with the reference ratio, the change condition of the electro-optical conversion coefficient K can be determined according to the comparison result, and the amplification factor of the second amplifier U2 can be correspondingly adjusted.

In one embodiment, the resistance value of the resistor R1 may be configured to be equal to the reference electro-optical conversion coefficient of the electro-optical conversion module 20. The reference electro-optical conversion coefficient of the electro-optical conversion module 20 is the electro-optical conversion coefficient when the laser diode LD1 is not affected by the temperature drift. At this time, as shown in fig. 8, the control module 50 is further configured to perform the following method steps:

step 801: a first reference ratio of the first voltage to the second voltage is determined to be 1.

Step 802: and if the first reference ratio is equal to the first ratio, keeping the amplification factor of the signal amplification module unchanged.

Step 803: and if the first reference ratio is larger than the first ratio, reducing the amplification factor of the signal amplification module.

Step 804: and if the first reference ratio is smaller than the first ratio, increasing the amplification factor of the signal amplification module.

The first reference ratio is a reference ratio of the first voltage V1 to the second voltage V2.

Specifically, when the first reference ratio is equal to the first ratio obtained in real time, it is indicated that the electro-optical conversion coefficient of the laser diode LD1 does not drift in temperature, and at this time, the amplification factor (i.e., gain) of the second amplifier U2 is not required to be adjusted.

When the first reference ratio is smaller than the first ratio, it is indicated that the electro-optical conversion coefficient of the laser diode LD1 becomes smaller due to temperature drift, and at this time, the amplification factor of the second amplifier U2 needs to be increased. Then, the second voltage V2 increases, and it can be determined from the formula (1) in the above embodiment that the actual electro-optical conversion coefficient of the laser diode LD1 also increases. And stopping increasing the amplification factor of the second amplifier U2 until the first reference ratio is equal to the first ratio.

When the first reference ratio is larger than the first ratio, it is explained that the electro-optical conversion coefficient of the laser diode LD1 is increased due to the temperature drift, and the amplification factor of the second amplifier U2 is reduced. Then, the second voltage V2 decreases, and it can be determined from the formula (1) in the above embodiment that the actual electro-optical conversion coefficient of the laser diode LD1 also decreases. And stopping reducing the amplification factor of the second amplifier U2 until the first reference ratio is equal to the first ratio.

Wherein the first ratio may be obtained in accordance with the manner provided in the above-described embodiments, i.e. from the ratio of the pulse width of the first comparison pulse to the pulse width of the second comparison pulse.

It can be understood that in this embodiment, since the first reference ratio is 1, the amplification factor of the second amplifier U2 is adjusted in the above manner, and the first voltage V1 and the second voltage V2 can be completely equal, so that the accuracy can be prevented from being affected due to the non-constant voltages of the first voltage V1 and the second voltage V2, in other words, the accuracy of this manner is high.

In addition, the waveform shapes and the frequency spectrums of the first voltage V1 and the second voltage V2 are dependent on the input voltage VIN, and the waveform shapes and the frequency spectrums of the first voltage V1 and the second voltage V2 may be very complex. Methods frequently employed in the related art, such as measuring an average value, an effective value, a low-frequency waveform, and the like of the two voltages, are not high in accuracy. In the embodiment of the application, the method is used for synchronously comparing the waveforms of the first voltage V1 and the second voltage V2 in real time, so that accurate comparison accuracy can be achieved regardless of the waveform shape and the frequency spectrum of the first voltage V1 and the second voltage V2.

The embodiment of the application also provides another way of adjusting the amplification factor of the second amplifier U2. In one embodiment, as shown in FIG. 9, the control module 50 is further configured to perform the following method steps:

step 901: a reference electro-optic conversion coefficient of the electro-optic conversion module is determined.

Step 902: a second reference ratio of the first voltage to the second voltage is determined based on the reference voltage conversion coefficient.

Step 903: and if the second reference ratio is equal to the first ratio, keeping the amplification factor of the signal amplification module unchanged.

Step 904: and if the second reference ratio is larger than the first ratio, reducing the amplification factor of the signal amplification module.

Step 905: and if the second reference ratio is smaller than the first ratio, increasing the amplification factor of the signal amplification module.

The second reference ratio is a reference ratio of the first voltage V1 to the second voltage V2.

The reference electro-optical conversion coefficient of the electro-optical conversion module 20 may be determined by the formula (2) when the temperature drift of the electro-optical conversion module 20 does not occur, or may be obtained by other means, which is not particularly limited in the embodiment of the present application.

Specifically, the second reference ratio can be obtained by substituting the conversion coefficient based on the reference voltage into the formula (3) in the above embodiment.

When the second reference ratio is equal to the first ratio obtained in real time, it is indicated that the electro-optical conversion coefficient of the laser diode LD1 does not drift at any temperature, and the amplification factor (i.e., gain) of the second amplifier U2 does not need to be adjusted.

When the second reference ratio is smaller than the first ratio, it is indicated that the electro-optical conversion coefficient of the laser diode LD1 becomes smaller due to temperature drift, and at this time, the amplification factor of the second amplifier U2 needs to be increased. Then, the second voltage V2 increases, and it can be determined from the formula (1) in the above embodiment that the actual electro-optical conversion coefficient of the laser diode LD1 also increases. And stopping increasing the amplification factor of the second amplifier U2 until the second reference ratio is equal to the first ratio.

When the second reference ratio is larger than the first ratio, it is indicated that the electro-optical conversion coefficient of the laser diode LD1 is increased due to the temperature drift, and the amplification factor of the second amplifier U2 is reduced. Then, the second voltage V2 decreases, and it can be determined from the formula (1) in the above embodiment that the actual electro-optical conversion coefficient of the laser diode LD1 also decreases. And stopping reducing the amplification factor of the second amplifier U2 until the second reference ratio is equal to the first ratio.

Further, it should be noted that the hardware configuration of the laser signal transmission system 100 as shown in fig. 7 is only one example, and the laser signal transmission system 100 may have more or less components than those shown in the drawings, may combine two or more components, or may have different component configurations, and various components shown in the drawings may be implemented in hardware, software, or a combination of hardware and software including one or more signal processing and/or application specific integrated circuits.

For example, as shown in fig. 10, the laser signal transmission system 100 further includes a second digital fiber transmitter 90 and a second digital fiber receiver 90a.

Wherein, the first end of the second digital optical fiber transmitter 90 is connected to the output end of the first comparator U5, the second end of the second digital optical fiber transmitter 90 is connected to the first end of the second digital optical fiber receiver 90a through the digital optical fiber 400, and the second end of the second digital optical fiber receiver 90a is connected to the first end of the control module 50.

Specifically, the first comparison pulse output by the first comparator U5 is transmitted to the control module 50 through the second digital fiber transmitter 90 and the second digital fiber receiver 90a.

In another embodiment, the laser signal transmission system 100 further comprises a subtractor U7.

The subtracter U7 is connected to the signal amplifying module 40 and the control module 50, respectively. Specifically, the noninverting input terminal of the subtractor U7 is connected to the output terminal of the second amplifier U2, the inverting input terminal of the subtractor U7 is connected to the fifth terminal of the control module 50, and the output terminal of the subtractor U7 is used for outputting the voltage VOUT.

Specifically, the control module 50 is further configured to obtain a static operating current of the electro-optical conversion module 20, and output a third voltage (denoted as a third voltage V3) corresponding to the static operating current to the subtractor. When the input voltage VIN is 0, the current flowing through the electro-optical conversion module 20 is a static operating current. The subtractor U7 is configured to generate the output voltage VOUT based on a difference between the second voltage V2 and the third voltage V3.

The static working current Is already described in the above embodiments, and will not be described herein.

In this embodiment, the second voltage V2 further includes a dc voltage signal (i.e., the third voltage V3) corresponding to the quiescent operating current Is of the laser diode LD 1. By providing the subtractor U3, the third voltage V3 corresponding to the static operating current Is subtracted from the second voltage V2, and an output voltage VOUT proportional to the input voltage VIN Is obtained.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present application, and are not limiting; the technical features of the above embodiments or in the different embodiments may also be combined within the idea of the application, the steps may be implemented in any order, and there are many other variations of the different aspects of the application as described above, which are not provided in detail for the sake of brevity; although the application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the application.

Claims

1. A laser signal transmission system, comprising:

2. The laser signal transmission system of claim 1, further comprising a waveform generation module, a first comparison module, and a second comparison module;

3. The laser signal transmission system of claim 2, wherein the waveform generation module comprises a first waveform generator, a second waveform generator, a first digital fiber transmitter, and a first digital fiber receiver;

4. A laser signal transmission system as claimed in any one of claims 1 to 3, wherein the control module is further adapted to:

5. The laser signal transmission system of claim 4, wherein the electrical signal generation module comprises a first amplifier and a power transistor;

6. The laser signal transmission system of claim 5, wherein the electrical signal generation module further comprises a resistor, a first subtractor, and a second subtractor;

7. The laser signal transmission system of claim 6, wherein the first voltage is: v1=r1 (ILD 1-Ith), where V1 is the first voltage and R1 is the resistance value of the resistor.

8. The laser signal transmission system according to claim 7, wherein a resistance value of the resistor is configured to be equal to a reference electro-optical conversion coefficient of the electro-optical conversion module;

the control module is further configured to:

9. The laser signal transmission system of claim 1, wherein the control module is further configured to:

10. The laser signal transmission system of claim 1, wherein the electro-optic conversion module comprises a laser diode,

11. The laser signal transmission system of claim 1, wherein the photoelectric conversion module comprises a photodiode;

12. The laser signal transmission system of claim 1, further comprising a subtractor, the subtractor being respectively connected to the signal amplification module and the control module;