Direct modulation laser and optical communication equipment

Abstract

The invention relates to the field of optical communication, and discloses a direct modulation laser and optical communication equipment. The direct modulation laser comprises a driving module, a differential module, an impedance adjusting module and a laser generating module. The driving module is configured to receive a pair of input signals and differentially amplify the input signals into a pair of modulation signals. And the differential module is configured to sample the modulation signal and differentiate the voltage waveform of the modulation signal obtained by sampling to obtain a differential signal. The impedance adjusting module is configured to generate an impedance control signal based on the waveform of the differential signal; the impedance control signal is used for controlling the output impedance of the driving module so as to control the waveform of the modulation signal. And the laser generation module is configured to generate laser in response to the modulation signal.

Description

Technical Field

[0001] The present application relates to the field of optical communications, and in particular to a directly modulated laser and optical communication equipment. Background Art

[0002] As the scale of the Internet expands, optical communication technology is rapidly applied to high-speed data transmission. Optical communication systems usually include: lasers, optical fibers and photodetectors. Among them, lasers can convert electrical signals into optical signals; optical fibers are used to transmit optical signals generated by lasers; and photodetectors are set at the end of optical fibers to convert optical signals back into electrical signals.

[0003] The laser is set at the transmitting end of the optical communication system, and it requires a special driving circuit to work. Common driving methods include electro-optically modulated laser (EML) and directly modulated laser (DML). Among them, the working principle of DML is to modulate the amplitude and phase of the optical signal based on the change of carrier concentration in the semiconductor material. Compared with EML, DML has the advantages of low cost, low power consumption and easy integration. Therefore, DML has a wide range of applications in optical communication, optical computing and optical sensing.

[0004] However, due to different manufacturing processes, the available laser generation modules have different impedances. Thus, the driving circuit needs to face load impedances with different characteristics, and the change of load impedance will directly affect the signal transmission quality and circuit stability. Summary of the invention

[0005] In view of this, an embodiment of the present application provides a directly modulated laser and an optical communication device, which can improve the transmission quality of signals and the stability of circuits.

[0006] The technical solution of the embodiment of the present application is implemented as follows:

[0007] The embodiment of the present application provides a directly modulated laser, comprising: a driving module, a differential module, an impedance adjustment module and a laser generating module; the input end of the differential module is connected to the output end of the driving module; the input end of the impedance adjustment module is connected to the output end of the differential module, and the output end of the impedance adjustment module is connected to the control end of the driving module; the laser generating module is connected to the output end of the driving module; the driving module is configured to receive a pair of input signals and differentially amplify the input signals into a pair of modulation signals; the differential module is configured to sample the modulation signal and differentiate the voltage waveform of the sampled modulation signal to obtain a differential signal; the impedance adjustment module is configured to generate an impedance control signal based on the waveform of the differential signal; the impedance control signal is used to control the output impedance of the driving module, thereby controlling the waveform of the modulation signal; the laser generating module is configured to generate laser in response to the modulation signal.

[0008] In some embodiments of the present application, the impedance adjustment module is also configured to generate the corresponding impedance control signal based on the reflected waveform in the differential signal to adjust the output impedance of the driving module until the reflected waveform is eliminated; wherein the reflected waveform is generated by the reflection of the modulated signal.

[0009] In some embodiments of the present application, the impedance adjustment module includes: a band-stop filter, a delay circuit, a subtractor and a logic processing unit; the input end of the band-stop filter receives the differential signal; the input end of the delay circuit and the first input end of the subtractor are both connected to the output end of the band-stop filter; the second input end of the subtractor is connected to the output end of the delay circuit; the input end of the logic processing unit is connected to the output end of the subtractor; the output end of the logic processing unit outputs the impedance control signal; the band-stop filter is configured to filter the main waveform in the differential signal and retain the reflected waveform in the differential signal; the subtractor is configured to subtract the reflected waveform that has not been delayed from the reflected waveform that has been delayed; the logic processing unit is configured to output the impedance control signal to adjust the output impedance of the driving module until the amplitude of the output signal of the subtractor is reduced to within a threshold range.

[0010] In some embodiments of the present application, the delay amount of the delay circuit is less than half of the period of the modulation signal.

[0011] In some embodiments of the present application, the driving module includes: a first adjustable impedance, a second adjustable impedance, a first voltage source, a second voltage source, a first bridge T coil, a second bridge T coil, a first driving transistor, a second driving transistor and a current source; wherein the first end of the first adjustable impedance is connected to the first voltage source; the second end of the first adjustable impedance is connected to the first end of the first bridge T coil; the second end of the first bridge T coil is connected to the first end of the first driving transistor; the second end of the first driving transistor is connected to the first end of the current source; the second end of the current source is connected to the ground terminal; the first end of the second adjustable impedance is connected to the second voltage source; the second end of the second adjustable impedance is connected to the first end of the second bridge T coil; the second end of the second bridge T coil is connected to the first end of the second driving transistor; the second end of the second driving transistor is connected to the first end of the current source; the control end of the first driving transistor receives a first input signal; the control end of the second driving transistor receives a second input signal; the third end of the first bridge T coil outputs a first modulation signal; the third end of the second bridge T coil outputs a second modulation signal; the control end of the first adjustable impedance and the control end of the second adjustable impedance receive the corresponding impedance control signal respectively.

[0012] In some embodiments of the present application, each adjustable impedance includes: n resistance branches connected in parallel; n is greater than 1; each of the resistance branches includes: a resistor and a control transistor connected in series; wherein the control end of the control transistor receives a corresponding bit signal in the impedance control signal.

[0013] In some embodiments of the present application, the ratio of the resistance values ​​of the resistors in the n resistor branches is 1:2:4:...:2 n-1 .

[0014] In some embodiments of the present application, each bridge T coil includes: a first inductor, a second inductor and a first capacitor; the first inductor, the second inductor and the first capacitor are connected in series in sequence to form a coil; wherein the connection end of the first inductor and the first capacitor serves as the first end of the bridge T coil; the connection end of the second inductor and the first capacitor serves as the third end of the bridge T coil; the connection end of the first inductor and the second inductor serves as the second end of the bridge T coil.

[0015] In some embodiments of the present application, the differential module includes: a first transistor, a second transistor and a second capacitor; the first end of the first transistor is connected to the first end of the second capacitor and to the ground terminal; the first end of the second transistor is connected to the second end of the second capacitor and to the ground terminal; the control end of the first transistor and the control end of the second transistor respectively receive the pair of modulation signals; the first end of the first transistor and the first end of the second transistor output the differential signal.

[0016] An embodiment of the present application also provides an optical communication device, including: the directly modulated laser described in the above solution.

[0017] It can be seen that the directly modulated laser provided in the embodiment of the present application can generate a corresponding impedance control signal based on the differential signal to adjust the output impedance of the driving module. In this way, the output impedance of the driving module can be controlled to match the impedance of the laser generating module, thereby improving the signal transmission quality and the stability of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of the structure of a directly modulated laser provided in an embodiment of the present application;

[0019] Figure 2A The waveform of the modulation signal in the embodiment of the present application is shown as follows: Figure 1 ;

[0020] Figure 2B The waveform of the differential signal in the embodiment of the present application is shown as follows: Figure 1 ;

[0021] Figure 3A Schematic diagram 2 of the waveform of the modulation signal in the embodiment of the present application;

[0022] Figure 3B Schematic diagram 2 of the waveform of the differential signal in the embodiment of the present application;

[0023] Figure 4 A schematic diagram of the structure of an impedance adjustment module in a directly modulated laser provided in an embodiment of the present application;

[0024] Figure 5 A schematic diagram of the structure of a driving module in a directly modulated laser provided in an embodiment of the present application;

[0025] Figure 6 A schematic diagram of the structure of the adjustable impedance in the directly modulated laser provided in an embodiment of the present application;

[0026] Figure 7 A schematic diagram of the structure of a differential module in a directly modulated laser provided in an embodiment of the present application;

[0027] Figure 8 A schematic diagram of the structure of an optical communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the present application clearer, the technical solutions of the present application are further elaborated in detail below in conjunction with the drawings and embodiments. The described embodiments should not be regarded as limiting the present application. All other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0029] In the following description, reference is made to “some embodiments”, which describe a subset of all possible embodiments, but it will be understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0030] If similar descriptions of "first / second" appear in the application documents, the following description is added. In the following description, the terms "first / second / third" involved are merely used to distinguish similar objects and do not represent a specific ordering of the objects. It is understandable that "first / second / third" can be interchanged in a specific order or sequence where permitted, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0032] Figure 1 This is an optional structural diagram of a directly modulated laser provided in an embodiment of the present application.

[0033] like Figure 1 As shown, the directly modulated laser includes: a driving module 10, a differential module 20, an impedance adjustment module 30 and a laser generating module 40. Among them, the input end of the differential module 20 is connected to the output end of the driving module 10; the input end of the impedance adjustment module 30 is connected to the output end of the differential module 20, and the output end of the impedance adjustment module 30 is connected to the control end of the driving module 10; the laser generating module 40 is connected to the output end of the driving module 10.

[0034] refer to Figure 1The driving module 10 is configured to receive a pair of input signals INN and INP, and differentially amplify the input signals into a pair of modulation signals OUTN and OUTP. The differentiation module 20 is configured to sample the modulation signals OUTN and OUTP, and differentiate the voltage waveforms of the sampled modulation signals OUTN and OUTP to obtain a differential signal OUTD. The impedance adjustment module 30 is configured to generate an impedance control signal VC based on the waveform of the differential signal OUTD; the impedance control signal VC is used to control the output impedance of the driving module 10, thereby controlling the waveforms of the modulation signals OUTN and OUTP. The laser generation module 40 is configured to generate laser in response to the modulation signals OUTN and OUTP.

[0035] It should be noted that if the output impedance of the driving module 10 does not match the impedance of the laser generating module 40, the modulation signals OUTN and OUTP will be reflected, thereby affecting the waveforms of the modulation signals OUTN and OUTP, and further affecting the signal transmission quality and circuit stability.

[0036] Figure 2A The waveform of the modulation signal OUTN or OUTP when there is no reflection is shown in the example. Figure 3A The waveform of the modulation signal OUTN or OUTP at the time of reflection is illustrated.

[0037] refer to Figure 2A , when there is no reflection, the waveform of the modulation signal OUTN or OUTP is a standard square wave. Figure 3A When there is reflection, the waveform of the modulation signal OUTN or OUTP is affected by the reflected signal and becomes deformed, and is no longer a standard square wave.

[0038] Figure 2B The example shows the waveform of the differential signal OUTD when there is no reflection, that is, Figure 2A After differentiating the waveform shown in the example, we can get Figure 2B Example waveform. Figure 3B The waveform of the differential signal OUTD during reflection is shown in the example, that is, Figure 3A After differentiating the waveform shown in the example, we can get Figure 3B Example waveform.

[0039] because Figure 3A The waveform of the modulation signal OUTN or OUTP in the circuit is deformed by the reflected signal. Figure 3B The waveform of the differential signal OUTD includes not only the main waveform but also the reflected waveform. The main waveform of the differential signal OUTD is obtained by differentiating the change of the square wave waveform of the modulation signal OUTN or OUTP, that is, Figure 2BThe waveform shown in FIG. 1; The reflected waveform of the differential signal OUTD is generated by the reflection of the modulation signal OUTN or OUTP, that is, Figure 3B compared to Figure 2B The extra waveform.

[0040] In the embodiment of the present application, the impedance adjustment module 30 can generate a corresponding impedance control signal VC based on the reflected waveform in the differential signal OUTD to adjust the output impedance of the driving module 10 until the reflected waveform is eliminated. In this way, the output impedance of the driving module 10 can be controlled to match the impedance of the laser generating module 40, thereby improving the signal transmission quality and the stability of the circuit.

[0041] It can be understood that the embodiments of the present application have the following advantages:

[0042] (i) Dynamic adjustment: The output impedance of the driving module 10 is adjusted quickly and continuously through the impedance control signal VC, so that the directly modulated laser provided by the present application has stronger adaptability to the laser generating modules 40 with different impedances;

[0043] (ii) Simple control: The reflection of the modulation signals OUTN and OUTP is detected by differentiating the voltage waveforms of the modulation signals OUTN and OUTP, thereby reducing the complexity of the control circuit and the chip area;

[0044] (III) Improved efficiency: The matching degree between the driving module 10 and the laser generating module 40 is optimized, the transmission efficiency of the signal is improved, and the inter-symbol interference of the optical communication is reduced;

[0045] (IV) Reduce costs: Compared with fixed output impedance, variable output impedance can reduce R&D and production costs.

[0046] In some embodiments of the present application, Figure 4 As shown, the impedance adjustment module 30 includes: a band stop filter 301, a delay circuit 302, a subtractor 303 and a logic processing unit 304. The input end of the band stop filter 301 receives the differential signal OUTD. The input end of the delay circuit 302 and the first input end of the subtractor 303 are both connected to the output end of the band stop filter 301. The second input end of the subtractor 303 is connected to the output end of the delay circuit 302. The input end of the logic processing unit 304 is connected to the output end of the subtractor 303. The output end of the logic processing unit 304 outputs the impedance control signal VC.

[0047] In the present application embodiment, combined Figure 4 and Figure 3BThe band-stop filter 301 is configured to filter the main waveform in the differential signal OUTD and retain the reflected waveform D1 in the differential signal OUTD. That is, the band-stop filter 301 can filter out the signal change rate equivalent to the transmission rate.

[0048] In the present application embodiment, combined Figure 4 and Figure 3B The subtractor 303 is configured to subtract the non-delayed reflected waveform D1 from the delayed reflected waveform D2. The logic processing unit 304 is configured to output an impedance control signal VC to adjust the output impedance of the driving module until the amplitude of the output signal of the subtractor 303 is reduced to within the threshold range.

[0049] It should be noted that, under the action of the impedance control signal VC, the output impedance of the driving module is regulated in real time, that is, the reflected waveform in the differential signal OUTD is regulated in real time; therefore, the reflected waveform D1 that has not been delayed is subtracted from the reflected waveform D2 that has been delayed, that is, the reflected waveform D1 at the current moment is subtracted from the reflected waveform D2 at the previous moment, which is equivalent to subtracting the reflected waveform D1 after regulation from the reflected waveform D2 before regulation. In this way, the output signal of the subtractor 303 actually reflects the difference between the reflected waveform D1 after regulation and the reflected waveform D2 before regulation; therefore, when the amplitude of the output signal of the subtractor 303 is reduced to within the threshold range (i.e., approaching 0), it means that the reflected waveform in the differential signal OUTD has been regulated to the minimum amplitude, and continued regulation cannot further reduce the amplitude of the reflected waveform, but may increase the amplitude of the reflected waveform.

[0050] In the embodiment of the present application, the impedance control signal VC output by the logic processing unit 304 can control the output impedance of the driving module to gradually increase or gradually decrease to approach the most matched impedance value, so that the amplitude of the reflected waveform in the differential signal OUTD is minimized. For example, the adjustment range of the output impedance of the driving module is 5Ω to 25Ω, then the output impedance of the driving module can be controlled to gradually increase from 5Ω, or the output impedance of the driving module can be controlled to gradually decrease from 25Ω until the amplitude of the output signal of the subtractor 303 is reduced to within the threshold range (i.e., approaching 0).

[0051] In some embodiments of the present application, the delay amount of the delay circuit 302 is less than half of the period of the modulation signal OUTD. Figure 3B In this way, it can be ensured that the reflected waveform subtracted by the subtractor 303 is located in the same time segment, that is, between the same two main waveforms; thereby, subtracting reflected waveforms in different segments is avoided, and the validity of the output signal of the subtractor 303 is guaranteed.

[0052] It can be understood that by subtracting the undelayed reflected waveform D1 from the delayed reflected waveform D2, the difference between the reflected waveform after regulation and the reflected waveform before regulation can be obtained, thereby feeding back the effect of regulation. In this way, the reflected waveform in the differential signal OUTD can be regulated to the minimum amplitude, that is, the output impedance of the driving module is matched with the impedance of the laser generating module.

[0053] In some embodiments of the present application, Figure 5 As shown, the driving module 10 includes: two adjustable impedances 101 and 102, two bridge T-coils 103 and 104, two driving transistors Q1 and Q2, and a current source Is. Among them, the first end of the first adjustable impedance 101 is connected to the first voltage source VCC1; the second end of the first adjustable impedance 101 is connected to the first end of the first bridge T-coil 103; the second end of the first bridge T-coil 103 is connected to the first end of the first driving transistor Q1; the second end of the first driving transistor Q1 is connected to the first end of the current source Is; the second end of the current source Is is connected to the ground terminal; the first end of the second adjustable impedance 102 is connected to the second voltage source VCC2; the second end of the second adjustable impedance 102 is connected to the first end of the second bridge T-coil 104; the second end of the second bridge T-coil 104 is connected to the first end of the second driving transistor Q2; the second end of the second driving transistor Q2 is connected to the first end of the current source Is.

[0054] In the present application examples, reference Figure 5 The control end of the first driving transistor Q1 receives the first input signal INN; the control end of the second driving transistor Q2 receives the second input signal INP. The third end of the first bridge T coil 103 outputs the first modulation signal OUTN; the third end of the second bridge T coil 104 outputs the second modulation signal OUTP. The control end of the first adjustable impedance 101 and the control end of the second adjustable impedance 102 receive the corresponding impedance control signal VC respectively.

[0055] In the embodiment of the present application, the input signals INN and INP are a pair of differential signals, which respectively control the on and off of the two driving transistors Q1 and Q2. When the first driving transistor Q1 is turned on, the second driving transistor Q2 is turned off; correspondingly, when the second driving transistor Q2 is turned on, the first driving transistor Q1 is turned off. The third end of the first bridge T coil 103 and the third end of the second bridge T coil 104 serve as the output end of the driving module 10, and output a pair of modulation signals OUTN and OUTP.

[0056] In the embodiment of the present application, the driving module 10 uses two voltage sources VCC1 and VCC2 to provide voltage, and the voltage values ​​provided by the two voltage sources VCC1 and VCC2 are different.

[0057] In the embodiment of the present application, the driving module 10 uses two bridge T coils 103 and 104. In this way, on the one hand, the bridge T coil can keep the output impedance of the driving module 10 stable at various frequencies, and prevent the output impedance of the driving module 10 from being affected by frequency changes; on the other hand, compared with the parallel peaking and series peaking structures, the bridge T coil structure can provide a larger bandwidth increment, thereby improving the bandwidth of the optical communication system.

[0058] In some embodiments of the present application, Figure 5 As shown, each bridge T coil includes: a first inductor, a second inductor and a first capacitor.

[0059] In the first bridge T coil 103, the first inductor L1a, the second inductor L2a and the first capacitor C1a are connected in series in sequence to form a coil; wherein the connection end of the first inductor L1a and the first capacitor C1a serves as the first end of the first bridge T coil 103, connected to the second end of the first adjustable impedance 101; the connection end of the second inductor L2a and the first capacitor C1a serves as the third end of the first bridge T coil 103, outputting the first modulation signal OUTN; the connection end of the first inductor L1a and the second inductor L2a serves as the second end of the first bridge T coil 103, connected to the first end of the first driving transistor Q1.

[0060] Correspondingly, in the second bridge T coil 104, the first inductor L1b, the second inductor L2b and the first capacitor C1b are connected in series in sequence to form a coil; wherein, the connection end of the first inductor L1b and the first capacitor C1b serves as the first end of the second bridge T coil 104, connected to the second end of the first adjustable impedance 102; the connection end of the second inductor L2b and the first capacitor C1b serves as the third end of the second bridge T coil 104, outputting the second modulation signal OUTP; the connection end of the first inductor L1b and the second inductor L2b serves as the second end of the second bridge T coil 104, connected to the first end of the second driving transistor Q2.

[0061] In the embodiment of the present application, the resistance values ​​of the two adjustable impedances 101 and 102 are controlled by the impedance control signal VC. By changing the impedance control signal VC, the resistance values ​​of the adjustable impedances 101 and 102 can be changed, so that the output impedance of the driving module 10 can be adjusted to make the output impedance of the driving module 10 as close as possible to the impedance of the laser generating module 40. In the process of adjusting the output impedance of the driving module 10, the resistance values ​​of the adjustable impedances 101 and 102 need to be kept equal or maintain a predetermined multiple relationship, so as to ensure that the driving module 10 can well realize the differential amplification function.

[0062] In some embodiments of the present application, Figure 6As shown, each adjustable impedance (first adjustable impedance 101 or second adjustable impedance 102) includes: n resistor branches connected in parallel; n is greater than 1. Each resistor branch includes: a resistor and a control transistor connected in series; wherein the control end of the control transistor receives a corresponding bit signal in the impedance control signal. The impedance control signal can control one or more of the n resistor branches to be turned on, thereby controlling the total impedance value of the adjustable impedance.

[0063] refer to Figure 6 The first resistance branch includes a resistor R1 and a control transistor MC1 connected in series, and the control end of the control transistor MC1 receives the sub-signal C1 of the impedance control signal; the second resistance branch includes a resistor R2 and a control transistor MC2 connected in series, and the control end of the control transistor MC2 receives the sub-signal C2 of the impedance control signal; the third resistance branch includes a resistor R3 and a control transistor MC3 connected in series, and the control end of the control transistor MC3 receives the sub-signal C3 of the impedance control signal; the fourth resistance branch includes a resistor R4 and a control transistor MC4 connected in series, and the control end of the control transistor MC4 receives the sub-signal C4 of the impedance control signal.

[0064] In some embodiments of the present application, the ratio of the resistance values ​​of the resistors in the n resistor branches is 1:2:4:...:2 n -1 For example, refer to Figure 6 , R1:R2:R3:R4=1:2:4:8.

[0065] It can be understood that the resistance ratio of the resistors in the n resistor branches is set to 1:2:4:...:2 n-1 , then the total impedance value of the adjustable impedance can be 2 n Thus, the total impedance value range and the adjustment gradient of the adjustable impedance are effectively expanded, so that the directly modulated laser has stronger adaptability to laser generating modules with different impedances.

[0066] In some embodiments of the present application, Figure 7 As shown, the differential module 20 includes: a first transistor M1, a second transistor M2, and a second capacitor C2. The first end of the first transistor M1 is connected to the first end of the second capacitor C2, and is also connected to the ground terminal. The first end of the second transistor M2 is connected to the second end of the second capacitor C2, and is also connected to the ground terminal. The control end of the first transistor M1 and the control end of the second transistor M2 receive a pair of modulation signals OUTN and OUTP, respectively. The first end of the first transistor M1 and the first end of the second transistor M2 output differential signals OUTC and OUTD.

[0067] Figure 8 Schematic diagram of an optional structure of an optical communication device provided in an embodiment of the present application. Figure 8 As shown, the optical communication device 80 includes: a directly modulated laser 810. The directly modulated laser 810 has the technical features of the above-mentioned solution.

[0068] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0069] The serial numbers of the embodiments of the present application are for description only and do not represent the advantages and disadvantages of the embodiments. The methods disclosed in the several method embodiments provided in this application can be arbitrarily combined without conflict to obtain new method embodiments. The features disclosed in the several product embodiments provided in this application can be arbitrarily combined without conflict to obtain new product embodiments. The features disclosed in the several method or device embodiments provided in this application can be arbitrarily combined without conflict to obtain new method embodiments or device embodiments.

[0070] The above description is only a specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application.

Claims

1. A directly modulated laser, characterized in that: include: A driving module, a differentiating module, an impedance adjusting module and a laser generating module; The input end of the differential module is connected to the output end of the driving module; The input end of the impedance adjustment module is connected to the output end of the differential module, and the output end of the impedance adjustment module is connected to the control end of the driving module; the laser generation module is connected to the output end of the driving module; The driving module is configured to receive a pair of input signals and differentially amplify the input signals into a pair of modulated signals; The differentiation module is configured to sample the modulation signal, and differentiate the voltage waveform of the modulation signal obtained by sampling to obtain a differential signal; The impedance adjustment module is configured to generate an impedance control signal based on the waveform of the differential signal; The impedance control signal is used to control the output impedance of the driving module, thereby controlling the waveform of the modulation signal; The laser generating module is configured to generate laser light in response to the modulation signal.

2. The directly modulated laser according to claim 1, characterized in that: The impedance adjustment module is further configured to generate the corresponding impedance control signal based on the reflected waveform in the differential signal to adjust the output impedance of the driving module until the reflected waveform is eliminated; wherein the reflected waveform is generated by the reflection of the modulated signal.

3. The directly modulated laser according to claim 1, characterized in that: The impedance adjustment module includes: a band-stop filter, a delay circuit, a subtractor and a logic processing unit; The input end of the band stop filter receives the differential signal; the input end of the delay circuit and the first input end of the subtractor are both connected to the output end of the band stop filter; the second input end of the subtractor is connected to the output end of the delay circuit; the input end of the logic processing unit is connected to the output end of the subtractor; the output end of the logic processing unit outputs the impedance control signal; The band-stop filter is configured to filter the main waveform in the differential signal and retain the reflected waveform in the differential signal; The subtractor is configured to subtract the undelayed reflected waveform from the delayed reflected waveform; The logic processing unit is configured to output the impedance control signal to adjust the output impedance of the driving module until the amplitude of the output signal of the subtractor decreases to within a threshold range.

4. The directly modulated laser according to claim 3, characterized in that: The delay amount of the delay circuit is less than half of the period of the modulation signal.

5. The directly modulated laser according to claim 1, characterized in that: The driving module includes: a first adjustable impedance, a second adjustable impedance, a first voltage source, a second voltage source, a first bridge T coil, a second bridge T coil, a first driving transistor, a second driving transistor and a current source; wherein, The first end of the first adjustable impedance is connected to the first voltage source; the second end of the first adjustable impedance is connected to the first end of the first bridge T coil; the second end of the first bridge T coil is connected to the first end of the first driving transistor; the second end of the first driving transistor is connected to the first end of the current source; the second end of the current source is connected to the ground terminal; The first end of the second adjustable impedance is connected to the second voltage source; the second end of the second adjustable impedance is connected to the first end of the second bridge T coil; the second end of the second bridge T coil is connected to the first end of the second driving transistor; the second end of the second driving transistor is connected to the first end of the current source; The control terminal of the first driving transistor receives a first input signal; the control terminal of the second driving transistor receives a second input signal; The third end of the first bridge T coil outputs a first modulation signal; the third end of the second bridge T coil outputs a second modulation signal; The control end of the first adjustable impedance and the control end of the second adjustable impedance respectively receive the corresponding impedance control signal.

6. The directly modulated laser according to claim 5, characterized in that: Each adjustable impedance includes: n resistance branches connected in parallel; n is greater than 1; Each of the resistance branches includes: a resistor and a control transistor connected in series; wherein the control end of the control transistor receives a corresponding bit signal in the impedance control signal.

7. The directly modulated laser according to claim 6, characterized in that: The ratio of the resistance values ​​of the resistors in the n resistor branches is 1:2:4:...:2 n-1 .

8. The directly modulated laser according to claim 5, characterized in that: Each bridge T coil includes: a first inductor, a second inductor and a first capacitor; The first inductor, the second inductor and the first capacitor are sequentially connected in series to form a coil; Among them, the connection end of the first inductor and the first capacitor serves as the first end of the bridge T coil; the connection end of the second inductor and the first capacitor serves as the third end of the bridge T coil; and the connection end of the first inductor and the second inductor serves as the second end of the bridge T coil.

9. The directly modulated laser according to claim 1, characterized in that: The differential module includes: a first transistor, a second transistor and a second capacitor; The first end of the first transistor is connected to the first end of the second capacitor and is also connected to the ground terminal; the first end of the second transistor is connected to the second end of the second capacitor and is also connected to the ground terminal; The control end of the first transistor and the control end of the second transistor receive the pair of modulation signals respectively; the first end of the first transistor and the first end of the second transistor output the differential signal.

10. An optical communication device, characterized in that: include: A directly modulated laser as claimed in any one of claims 1 to 9.

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