External modulation-based burst drive and monitoring circuits, methods, and optical communication devices

Abstract

This invention belongs to the field of optical communication technology and provides a burst driving and monitoring circuit, method, and optical network unit based on external modulation. The burst driving and monitoring circuit based on external modulation includes a burst driving circuit, an optical emitting device, a burst monitoring circuit, and a controller. The burst driving circuit includes a laser driving module, which includes a first current source for outputting a set current; an inverter for inverting an externally input PWM control signal and then controlling the on / off state of a first controllable switch to achieve burst control of laser emission; the burst monitoring circuit for sampling the emitted optical power value of the laser, locking the emitted optical power value during the laser emission period, and monitoring it; the controller is connected to the burst monitoring circuit and is used to control the output current of the first current source based on the emitted optical power value monitoring results. It enables burst applications of high-speed 50Gbps and above optical modules and high-power, long-distance, high-speed signal transmission.

Description

Technical Field

[0001] This invention belongs to the field of optical communication technology, and particularly relates to a burst drive and monitoring circuit, method and optical communication device based on external modulation. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Broadband access network traffic is experiencing explosive growth due to applications such as high-definition video, AR / VR, and video conferencing. 50G PON, defined in the ITU-T G.hsp series of standards, includes: overall requirements, a general transmission aggregation layer, a physical media-related layer, and a TWDM (Time and Wavelength Division Multiplexed) physical media-related layer. The overall requirements are a single-wavelength 50G TDM PON architecture, with uplink TDMA / downlink TDM; support for different ONU rate combinations: 50G / 10G (home users), 50G / 25G (some home and enterprise users), and 50G / 50G (high-end customers); support for traditional ODN levels; support for coexistence and smooth evolution with XG(S)-PON and 10GEPON within the same ODN; supported distances: 20 kilometers (home and enterprise users), 10 kilometers (mobile bearer, latency-sensitive); and three DBA modes, among other features.

[0004] Since loss and dispersion are the main factors affecting the transmission distance of optical modules, traditional DML lasers (Directly Modulated Lasers) suffer from frequency chirp during modulation because the modulation signal directly drives the laser's intensity. This results in a relatively low optical signal-to-noise ratio. When the signal transmission speed exceeds 50Gbps, the modulation rate and complex modulation method limit the transmission distance, making it impossible to achieve transmission distances of 20km and above. Existing ONU optical modules based on DML lasers are only suitable for applications with speeds of 25Gbps and below, and are not suitable for burst applications of higher-speed optical modules (e.g., 50Gbps and above). Summary of the Invention

[0005] To address the technical problems existing in the background art, the present invention provides a burst drive and monitoring circuit, method and optical network unit based on external modulation, which can realize burst applications of higher speed (e.g. 50Gbps and above) optical modules as well as high-power, long-distance and high-speed signal transmission.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] The first aspect of the present invention provides a burst drive and monitoring circuit based on external modulation.

[0008] A burst drive and monitoring circuit based on external modulation, comprising:

[0009] Optical emitting devices, burst drive circuits, burst monitoring circuits, and controllers;

[0010] The optical emitting device includes a laser and a detector; the laser is used to generate laser light; the detector is connected to the laser and is used to detect the emitted light power value of the laser.

[0011] The burst drive circuit includes a laser drive module; the laser drive module includes a first current source, a first controllable switch, and an inverter; the input terminal of the first controllable switch is connected to the first controllable switch, the control terminal of the first controllable switch is connected to the inverter, and the output terminal of the first controllable switch is connected to the laser; the first current source is used to output a set current and transmit it to the laser via the first controllable switch; the inverter is used to invert the externally input PWM control signal and then control the on / off state of the first controllable switch to achieve burst control of laser emission;

[0012] The burst monitoring circuit is connected to the detector and is used to sample the emitted light power value of the laser detected by the detector, lock the emitted light power value during the laser emission period and monitor it.

[0013] The controller is connected to the burst monitoring circuit and is used to control the output current of the first current source based on the monitoring results of the emitted light power value, so as to control the laser to output light stably in a closed loop.

[0014] In one implementation, the burst monitoring circuit includes a mirror current source, a voltage sampling circuit, a hold circuit, and a signal detection circuit; the input terminal of the mirror current source is connected to the detector, the output terminal of the mirror current source is connected to the input terminal of the voltage sampling circuit, and the output terminal of the voltage sampling circuit is connected to the hold circuit and the signal detection circuit respectively; the mirror current source is used to output the current signal generated by the detector.

[0015] The voltage sampling circuit is used to convert the current signal output by the mirror current source into a voltage signal and sample it to obtain the emitted optical power value of the laser.

[0016] The signal detection circuit is used to detect the sampling signal of the voltage sampling circuit and output high and low level status indication signals to confirm whether the laser is in the emission period.

[0017] The holding circuit is used to lock the emitted light power value of the laser during the current emission period until the next emission period arrives, and then lock the emitted light power value of the next emission period when the next emission period arrives.

[0018] In one implementation, the holding circuit is also connected to a PWM pulse duty cycle adjustment circuit. The PWM duty cycle adjustment circuit is used to delay the falling edge of the input PWM signal, and through the conduction of the switching transistor, to enable the controller's data conversion interface to sample the emitted optical power value when the laser's emitted optical power is stable; and to accelerate the rising edge of the input PWM signal, and through the rapid turn-off of the switching transistor, to enable the holding circuit to latch the sampled emitted optical power value of the laser during the previous emission period.

[0019] In one embodiment, the optical emitting device further includes a modulator connected to the laser; the modulator is used to modulate the laser light generated by the laser.

[0020] In one embodiment, the burst drive circuit further includes a modulator drive module connected to the modulator; the modulator drive module is used to generate a drive signal for the modulator and, in conjunction with an adjustable negative bias voltage generated by a negative bias circuit, control the modulator's ability to absorb light intensity.

[0021] In one implementation, the modulator driver module includes a digital signal processor and a modulation signal driver, wherein the digital signal processor is connected to the modulation signal driver; the digital signal processor is used to generate a 50Gbps NRZ signal from two high-speed 25Gbps NRZ signals and transmit it to the modulation signal driver.

[0022] In one embodiment, the optical emitting device further includes a semiconductor optical amplifier connected to the output terminal of the modulator, which is used to amplify the optical signal modulated by the modulator.

[0023] In one embodiment, the burst drive circuit further includes a second current source connected to a semiconductor optical amplifier, which is used to control the amplification factor of the semiconductor optical amplifier.

[0024] A second aspect of the present invention provides a method for operating a burst drive and monitoring circuit based on external modulation.

[0025] A method for operating a burst drive and monitoring circuit based on external modulation, comprising:

[0026] The first current source outputs a set current and transmits it to the laser via the first controllable switch. The inverter inverts the externally input PWM control signal and then controls the on / off state of the first controllable switch to achieve burst control of laser emission.

[0027] The laser generates laser light based on burst control, and the detector detects the emitted light power of the laser.

[0028] The burst monitoring circuit samples the emitted light power value of the laser detected by the detector, locks the emitted light power value during the laser emission period, and monitors it.

[0029] The controller uses the monitored emission power value to provide feedback on the output current of the first current source, thereby achieving closed-loop control for stable laser emission.

[0030] A third aspect of the present invention provides an optical communication device.

[0031] An optical communication device includes the external modulation-based burst drive and monitoring circuit as described above.

[0032] The beneficial effects of this invention are:

[0033] (1) The burst drive and monitoring circuit based on external modulation of the present invention uses an inverter to invert the externally input PWM control signal and then controls the on / off state of the first controllable switch, thereby realizing burst control of whether the laser emits light.

[0034] (2) This invention utilizes the modulator’s drive signal and adjustable negative bias voltage to control the modulator’s ability to absorb light intensity, thereby enabling indirect modulation of optical signals. It can effectively suppress frequency chirp, enhance the signal-to-noise ratio of optical signals, reduce inter-symbol interference caused by signal dispersion, and enable burst applications of high-speed 50Gbps and above optical modules.

[0035] (3) The burst drive and monitoring circuit based on external modulation of the present invention also adds a semiconductor optical amplifier to amplify the power of the modulated optical signal of the modulator. This makes it suitable for high power splitting ratio application scenarios and greatly improves the output optical power.

[0036] (4) The present invention monitors the emitted light power value of the laser during the laser emission period and uses the emission power value monitoring result to control the output current of the first current source, thereby realizing the stability of the laser emission by closed-loop control.

[0037] (5) In the sudden monitoring circuit, the present invention uses a PWM pulse duty cycle adjustment circuit to delay the falling edge of the input PWM signal, and through the conduction of the switching transistor, enables the data conversion interface of the controller to sample the emitted light power value when the emitted light power of the laser is stable; and accelerates the response of the rising edge of the input PWM signal, and quickly turns off the switching transistor, so that the holding circuit latches the emitted light power value of the laser in the previous emission time period, ensuring that the stable value of the emitted light power of the laser can be sampled every time.

[0038] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0039] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0040] Figure 1 This is a schematic diagram of the burst drive and monitoring circuit based on external modulation according to an embodiment of the present invention;

[0041] Figure 2 This is a schematic diagram of the burst drive circuit and optical emitting device according to an embodiment of the present invention;

[0042] Figure 3 This is a schematic diagram of the burst monitoring circuit according to an embodiment of the present invention. Detailed Implementation

[0043] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0044] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0045] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0046] Example 1

[0047] according to Figure 1This embodiment provides a burst drive and monitoring circuit based on external modulation, which includes: a burst drive circuit, an optical emitting device, a burst monitoring circuit, and a controller.

[0048] The following diagrams illustrate the structure and working principle of the burst drive circuit, optical emitting device, and burst monitoring circuit:

[0049] (1) Burst drive circuit

[0050] according to Figure 1 and Figure 2 As shown, the burst drive circuit in this embodiment includes a laser drive module and a modulator drive module.

[0051] In this embodiment, the laser driving module includes a first current source, a first controllable switch, and an inverter. The input terminal of the first controllable switch is connected to the first controllable switch, the control terminal of the first controllable switch is connected to the inverter, and the output terminal of the first controllable switch is connected to the laser. The first current source is used to output a set current and transmit it to the laser via the first controllable switch. The inverter is used to invert the externally input PWM control signal (BEN signal) and then control the on / off state of the first controllable switch to achieve burst control of laser emission.

[0052] exist Figure 1 In this process, the first current source is implemented using a V / I current source.

[0053] The first current source is controlled by a controller, which controls the magnitude of the current output from the first current source to the laser.

[0054] like Figure 2 As shown, the first current source includes an arithmetic unit U2B, resistors R5, R7, R8, R9, and R11, and a MOSFET Q1A. The non-inverting input of the arithmetic unit U2B is connected to VDAC1 through R7, where VDAC1 is the voltage-type digital-to-analog converter interface of the controller, and its output voltage signal is a voltage signal. The inverting input of the arithmetic unit U2B is grounded through R8. The connection point between the non-inverting input of the arithmetic unit U2B and R7 is also connected to the drain of the MOSFET Q1A through R11. The drain of the MOSFET Q1A is also connected in series with R5. The source of the MOSFET Q1A is connected to the power supply VCC_4V, and the gate of the MOSFET Q1A is connected to the output of the arithmetic unit U2B. The drain of the MOSFET Q1A is also connected in series with R9 and R8.

[0055] Taking the first current source as an example, its working principle is as follows:

[0056] Let the voltage across resistor R5 be V1, the voltage across it be V2, and the non-inverting input of U2B be V. P The voltage at the inverting input terminal is equal to V. NThe operational amplifier has infinite input resistance. From the superposition law of linear resistor networks, we get:

[0057] V N =V1*R8 / (R8+R9);

[0058] V P =V2*R7 / (R7+R11)+V DAC *R11 / (R7+R11);

[0059] Because the V / I conversion drive circuit introduces voltage series negative feedback, it satisfies the virtual short V P =V N condition:

[0060] V P -V N =V2*R7 / (R7+R11)+V DAC *R11 / (R7+R11)-V1*R8 / (R8+R9)

[0061] When the condition R9 / R8=R11 / R7=k is satisfied, we get: V1-V2=k*V DAC ;

[0062] Magnitude of driving current Ibias: Ibias=(V1-V2) / R5=k*V DAC / R5.

[0063] according to Figure 2 The controllable switch is implemented using a MOSFET Q1B.

[0064] The inverter is implemented using resistors R13, R14, R17 and transistor U6.

[0065] The principle of BEN burst control is:

[0066] When BEN is low, transistor U6 is cut off, and the collector outputs a high level. At this time, the N-channel MOSFET Q1B is turned on, and the laser emits light normally.

[0067] When BEN is high, transistor U6 is turned on, and its collector outputs a low level. At this time, the N-channel MOSFET Q1B is turned off, and the laser does not emit light.

[0068] In this embodiment, the modulator driver module is connected to the modulator and is used to generate the modulator's drive signal and, in conjunction with the adjustable negative bias voltage generated by the negative bias circuit, control the modulator's ability to absorb light intensity.

[0069] Specifically, the modulator driver module includes a digital signal processor and a modulation signal driver. The digital signal processor is connected to the modulation signal driver. The digital signal processor is used to generate a 50Gbps NRZ signal from two high-speed 25Gbps NRZ signals and transmit it to the modulation signal driver.

[0070] like Figure 2 As shown, the digital signal processor is implemented using U3. The modulation signal driver is implemented using U1.

[0071] In the specific implementation process, the negative bias circuit is also connected to the controller. The negative bias circuit is used to convert the positive voltage output by the controller's digital-to-analog interface into a negative bias voltage and output it.

[0072] Within the set range: the lower the adjustable negative bias voltage, the stronger the modulator's ability to absorb light; the higher the adjustable negative bias voltage, the weaker the modulator's ability to absorb light.

[0073] according to Figure 2 The negative bias circuit is implemented using operational amplifier U2A and resistors R1, R2 and R4;

[0074] R2 is connected in series between the inverting input of operational amplifier U2A and the output of the controller; R4 is connected to the non-inverting input of operational amplifier U2A and is directly grounded; resistor R1 is connected between the inverting input and the output of operational amplifier U2A.

[0075] In this configuration, the Vcc of operational amplifier U2A is connected to GND, and GND is connected to the negative Vcc.

[0076] The output voltage of operational amplifier U2A is Vout = -V DAC *R1 / R2;

[0077] When V DAC The larger the output, the lower the negative bias voltage of the modulator EAM. Wherein, V DAC This is the voltage output by the controller, i.e., the voltage at the inverting input terminal of operational amplifier U2A.

[0078] (2) Light emitting device

[0079] according to Figure 1 and Figure 2 As shown, the optical emitting device in this embodiment includes a laser, a modulator, a semiconductor optical amplifier, and a detector; the laser is used to generate laser light; the modulator is connected to the laser and is used to modulate the laser light generated by the laser; the semiconductor optical amplifier is connected to the output terminal of the modulator and is used to amplify the optical signal modulated by the modulator; the detector is connected to the laser and is used to detect the emitted optical power value of the laser.

[0080] exist Figure 1 In this design, the laser is implemented using a DFB (Distributed Feedback Laser); the modulator is implemented using an EAM (Electro Absorption Modulation) modulator; and the detector can be implemented using a detector for MPD backlight monitoring. Figure 1 The SOA (Semi-conductor Optical Amplifier) ​​in this context is a semiconductor optical amplifier.

[0081] It should be noted that the laser, modulator, semiconductor optical amplifier, and detector can all be implemented using existing technologies, which will not be elaborated here.

[0082] In this embodiment, the amplification factor of the semiconductor optical amplifier is controlled by a second current source.

[0083] In practice, the second current source is also connected to a controller, which controls the second current source to adjust its output current. Figure 1 In this process, the second current source is implemented using a V / I current source.

[0084] like Figure 2 As shown, the second current source is implemented using an operational amplifier U5A.

[0085] The laser, modulator, semiconductor optical amplifier, and detector are all integrated in U4.

[0086] (3) Emergency monitoring circuit

[0087] according to Figure 1 and Figure 3 As shown, the burst monitoring circuit in this embodiment is connected to the detector and is used to sample the emitted light power value of the laser detected by the detector, lock the emitted light power value during the laser emission period and monitor it.

[0088] The controller is connected to the burst monitoring circuit and is used to control the output current of the first current source based on the monitoring results of the emitted light power value, so as to control the laser to output light stably in a closed loop.

[0089] The burst monitoring circuit includes a mirror current source, a voltage sampling circuit, a hold circuit, and a signal detection circuit. The input of the mirror current source is connected to the detector, the output of the mirror current source is connected to the input of the voltage sampling circuit, and the output of the voltage sampling circuit is connected to the hold circuit and the signal detection circuit, respectively.

[0090] The mirror current source is used to output the current signal generated by the detector; the voltage sampling circuit is used to convert the current signal output by the mirror current source into a voltage signal and sample it to obtain the emitted optical power value of the laser; the signal detection circuit is used to detect the sampling signal of the voltage sampling circuit and output high and low level status indication signals to confirm whether the laser is in the emission period; the holding circuit is used to lock the emitted optical power value of the laser in the current emission period until the next emission period arrives, and then lock the emitted optical power value of the next emission period when the next emission period arrives.

[0091] The negative supply voltage serves as the supply voltage for the mirror current source. For example... Figure 3 As shown, the current mirror source is implemented using U8 and U9. U8 and U9 are two identical NPN transistors. Because U9 has a U... BEO =U CEO Therefore, it can only operate in amplification mode. That is, the output current of the mirror current source is Imon = I C +2I B =I C +2*I C / β=I C *(β+1) / β; Since the amplification factor β is at least 100 times, Imon and I C Approximately equal. C and I B These are the collector and base currents of U8 and U9.

[0092] The holding circuit is also connected to the PWM pulse duty cycle adjustment circuit. The PWM duty cycle adjustment circuit is used to delay the falling edge of the input PWM signal, and through the conduction of the switching transistor (e.g., a microsecond-level delay switching transistor), the controller's data conversion interface samples the emitted optical power value when the laser's emitted optical power is stable; and to accelerate the response of the rising edge of the input PWM signal, and through the rapid turn-off of the switching transistor, the holding circuit latches the sampled emitted optical power value of the laser during the previous emission period.

[0093] Sampling voltage U ADC =2.5-R18*I C The larger the backlight current, the smaller the sampling voltage of the controller's data conversion interface ADC (Analog to Digital Converter). Let the sampling ADC value be X, and use the inverse formula (1-X / 4095)*2.4.

[0094] Hold circuit: The hold circuit consists of two voltage followers, one high-speed switch, and one PWM duty cycle adjustment circuit. Among them, U5B and U7A are both voltage followers composed of operational amplifiers, characterized by infinite input resistance, low output resistance, and fast response.

[0095] When the BEN input transitions from high to low, capacitor C10 discharges through resistor R19, gradually reducing the gate voltage of MOSFET Q2. The RC discharge time constant determines the delayed sampling time. When the voltage falls below the threshold voltage of the P-channel MOSFET, MOSFET Q2 turns on, rapidly charging capacitor C9; this is the sampling time. When the BEN input transitions from low to high, diode D2 rapidly charges C10, and MOSFET Q2 quickly turns off; this is the hold time. The RC delay circuit, composed of diode D2, resistor R19, and capacitor C10, achieves different delay processing for the rise and fall of the BEN control signal, enabling a microsecond-level sampling delay and a nanosecond-level fast hold time.

[0096] Transmitted signal detection circuit:

[0097] The voltage comparator composed of U7B outputs TX_SD at a high level when the non-inverting input voltage Up of U7B is greater than the inverting input voltage Un = 2.5 * R21 / (R21 + R20), indicating that the transmitted optical signal is normal. Conversely, the output TX_SD is at a low level when the non-inverting input voltage Up of U7B is greater than the inverting input voltage Un = 2.5 * R21 / (R21 + R20), indicating that there is no transmitted signal.

[0098] Example 2

[0099] This embodiment provides a method for operating a burst drive and monitoring circuit based on external modulation, including:

[0100] Step 1: The first current source outputs a set current and transmits it to the laser via the first controllable switch. The inverter inverts the externally input PWM control signal and then controls the on / off state of the first controllable switch to achieve burst control of laser emission.

[0101] Step 2: The laser generates a constant laser beam based on burst control, and the detector detects the emitted light power value of the laser.

[0102] Step 3: The burst monitoring circuit samples the emitted light power value of the laser, locks the emitted light power value during the laser emission period, and monitors it.

[0103] The controller uses the monitored emission power value to provide feedback on the output current of the first current source, thereby achieving closed-loop control for stable laser emission.

[0104] The working method of the burst drive and monitoring circuit based on external modulation in this embodiment realizes the burst application of high-speed 50Gbps and above optical modules as well as high-power, long-distance, and high-speed signal transmission.

[0105] Example 3

[0106] This embodiment provides an optical communication device, including the burst drive and monitoring circuit based on external modulation as described above.

[0107] It should be noted that, apart from the burst drive and monitoring circuit based on external modulation, the other structures of the optical network unit in this embodiment can be implemented using existing technologies, which will not be described in detail here.

[0108] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A burst drive and monitoring circuit based on external modulation, characterized in that, include: Optical emitting devices, burst drive circuits, burst monitoring circuits, and controllers; The optical emitting device includes a laser and a detector; The laser is used to generate laser light; The detector is connected to the laser and is used to detect the emitted light power value of the laser; The optical emitting device further includes a modulator connected to the laser; the modulator is used to modulate the laser light generated by the laser. The burst drive circuit includes a laser drive module; the laser drive module includes a first current source, a first controllable switch, and an inverter; the input terminal of the first controllable switch is connected to the first current source, the control terminal of the first controllable switch is connected to the inverter, and the output terminal of the first controllable switch is connected to the laser; the first current source is used to output a set current and transmit it to the laser via the first controllable switch. The inverter is used to invert the externally input PWM control signal and then control the on / off state of the first controllable switch to achieve burst control of laser emission. The burst monitoring circuit is connected to the detector and is used to sample the emitted light power value of the laser detected by the detector, lock the emitted light power value during the laser emission period and monitor it. The controller is connected to the burst monitoring circuit and is used to control the output current of the first current source based on the monitoring result of the emitted light power value, so as to control the laser to output light stably in a closed loop. The burst monitoring circuit includes a mirror current source, a voltage sampling circuit, a hold circuit, and a signal detection circuit; the input terminal of the mirror current source is connected to the detector, the output terminal of the mirror current source is connected to the input terminal of the voltage sampling circuit, and the output terminal of the voltage sampling circuit is connected to the hold circuit and the signal detection circuit respectively. The mirror current source is used to output the current signal generated by the detector; The voltage sampling circuit is used to convert the current signal output by the mirror current source into a voltage signal and sample it to obtain the emitted optical power value of the laser. The signal detection circuit is used to detect the sampling signal of the voltage sampling circuit and output high and low level status indication signals to confirm whether the laser is in the emission period. The holding circuit is used to lock the emitted light power value of the laser during the current emission time period until the next emission time period arrives, and then lock the emitted light power value of the next emission time period when the next emission time period arrives. The holding circuit is also connected to the PWM pulse duty cycle adjustment circuit. The PWM duty cycle adjustment circuit is used to delay the falling edge of the input PWM signal, and through the conduction of the switching transistor, enable the controller's data conversion interface to sample the emitted optical power value when the laser's emitted optical power is stable; and to accelerate the response of the rising edge of the input PWM signal, and through the rapid turn-off of the switching transistor, enable the holding circuit to latch the sampled emitted optical power value of the laser during the previous emission period.

2. The burst drive and monitoring circuit based on external modulation as described in claim 1, characterized in that, The burst drive circuit also includes a modulator drive module, which is connected to the modulator. The modulator drive module is used to generate a drive signal for the modulator and, in conjunction with the adjustable negative bias voltage generated by the negative bias circuit, control the modulator's ability to absorb light intensity.

3. The burst drive and monitoring circuit based on external modulation as described in claim 2, characterized in that, The modulator driver module includes a digital signal processor and a modulation signal driver, with the digital signal processor connected to the modulation signal driver. The digital signal processor is used to generate a 50Gbps NRZ signal from two high-speed 25Gbps NRZ signals and transmit it to the modulation signal driver.

4. The burst drive and monitoring circuit based on external modulation as described in claim 1, characterized in that, The optical emitting device also includes a semiconductor optical amplifier, which is connected to the output of the modulator and is used to amplify the optical signal modulated by the modulator.

5. The burst drive and monitoring circuit based on external modulation as described in claim 4, characterized in that, The burst drive circuit also includes a second current source, which is connected to a semiconductor optical amplifier and is used to control the amplification factor of the semiconductor optical amplifier.

6. The method of operating the burst drive and monitoring circuit based on external modulation as described in any one of claims 1-5, characterized in that, include: The first current source outputs a set current and transmits it to the laser via the first controllable switch. The inverter inverts the externally input PWM control signal and then controls the on / off state of the first controllable switch to achieve burst control of laser emission. The laser generates laser light based on burst control, and the detector measures the emitted light power of the laser. The burst monitoring circuit samples the emitted light power value of the laser detected by the detector, locks the emitted light power value during the laser emission period, and monitors it. The controller uses the monitored emission power value to provide feedback on the output current of the first current source, thereby achieving closed-loop control for stable laser emission.

7. An optical communication device, characterized in that, Includes the burst drive and monitoring circuit based on external modulation as described in any one of claims 1-5.

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