Light intensity sensing measurement device based on m-sequence pulse coding scheme

Abstract

The invention relates to a light intensity sensing measurement device based on an m-sequence pulse coding scheme. The light intensity sensing measurement device comprises a continuous laser; the coding signal generation circuit is used for generating a coding radio frequency signal with m-sequence intensity modulation; the optical input end of the light intensity modulator is connected to the continuous laser, the driving signal input end of the light intensity modulator is connected to the output end of the coded signal generation circuit, and first coded laser with m-sequence intensity modulation is output based on the coded radio-frequency signal and is incident into a sensing link to be measured; the signal acquisition unit is respectively connected with the coded signal generation circuit and the sensing link to be detected and is used for acquiring a backscattering signal of the sensing link to be detected under the action of the first coded laser, and the backscattering signal corresponds to the time interval of the coded radio frequency signal; and the signal data processing unit is connected with the signal acquisition unit and is used for obtaining the light intensity through slicing, cumulative averaging and cross-correlation operation in sequence based on the scattered signals. Compared with the prior art, the method has the advantages of improving the measurement precision and the response speed and the like.

Description

Technical Field

[0001] This invention relates to the field of optical measurement and sensing technology, and in particular to a light intensity sensing and measurement device based on an m-sequence pulse coding scheme. Background Technology

[0002] In the field of distributed fiber optic sensing, Rayleigh scattering, Brillouin frequency shift, and Raman scattering effects caused by intrinsic material defects and structural anisotropy result in a progressive attenuation during optical waveguide transmission that is exponentially related to the propagation distance. When the transmission distance exceeds the characteristic attenuation length, the backscattered photon flux density will fall below the detection sensitivity threshold, leading to a signal-to-noise ratio degradation below the detection limit, accompanied by a linear degradation of spatial resolution. This physical limitation makes traditional optical temporal reflectometry face a trade-off between spatial resolution and effective detection distance for long-distance monitoring.

[0003] Optical Time Domain Reflectometer (OTDR) technology enables multi-dimensional sensing of transmission links by analyzing the backscattered signals generated by propagating light pulses in optical fibers. Rayleigh scattering-based OTDRs can accurately locate fiber loss and vibration events by detecting fluctuations in elastic scattered light intensity caused by microscopic changes in the fiber's refractive index. Brillouin scattering OTDRs utilize the coupling effect between sound and light waves to achieve distributed strain and temperature measurements by analyzing changes in frequency shift. Raman scattering OTDRs, based on the dependence of inelastic scattered light intensity ratio on temperature, are specifically designed for monitoring temperature field distribution. These three technologies correspond to different physical mechanisms and complement each other in terms of spatial resolution, measurement parameters, and applicable scenarios. Innovative fusion sensing solutions, through coding modulation and signal decoupling techniques, can simultaneously extract multiple scattering features, breaking through the information dimension limitations of traditional single-mode OTDRs and providing a multi-parameter fusion solution for intelligent infrastructure monitoring.

[0004] In single-mode fiber optic sensing applications, traditional optical time-domain reflectometry (OTDR) technology faces significant technical bottlenecks: the backscattered signal transmitted in the reverse direction experiences an intensity attenuation of approximately 70 dB compared to the incident light power, causing the Rayleigh scattering signal amplitude to approach the detector's noise floor. This amplitude attenuation effect limits the system's dynamic range and degrades the signal-to-noise ratio, severely restricting long-distance monitoring capabilities and sensitivity for detecting weak events. To meet the requirements of industrial scenarios for detection distance and accuracy, existing solutions require the use of high-power pulsed light sources, but this leads to stimulated Brillouin scattering threshold limitations and fiber nonlinear effects (such as self-phase modulation), resulting in signal distortion and increased false alarm rates. Simultaneously, the surge in system power consumption, increased thermal management complexity, and shortened device lifespan caused by high-power light sources significantly increase deployment costs and maintenance difficulties, forming a core contradiction between technical feasibility and commercial viability.

[0005] In distributed fiber optic sensing systems, while optical amplifiers can enhance signal strength, they face significant technical limitations. The spontaneous emission noise they generate accumulates during multi-stage amplification, causing a signal-to-noise ratio degradation exceeding 5dB over long distances, severely impacting the accuracy of extracting weak scattered signals. Simultaneously, in applications with limited peak power (such as flammable and explosive environments requiring optical power below safety thresholds), the effective gain of the amplifier is significantly compressed due to nonlinear effect threshold limitations, failing to provide sufficient light intensity compensation. These two key issues collectively restrict the practical value of traditional optical amplification technology in industrial-grade long-distance monitoring. Summary of the Invention

[0006] The application of pulse code modulation (PCM) technology in distributed fiber optic sensing primarily overcomes the performance limitations of traditional detection methods by optimizing the temporal structure of optical pulses. This technology uses specific coding rules to modulate the phase or intensity of the probe light wave, generating a composite pulse sequence with excellent autocorrelation characteristics. At the receiver, digital signal processing algorithms are used to perform code matching and coherent accumulation on the backscattered signal, effectively enhancing the signal energy. The core advantages of this technology are twofold: first, it utilizes the random characteristics of the coded sequence to suppress coherent noise superposition, making the signal-to-noise ratio improvement proportional to the code length; second, it maintains the physical characteristics of individual symbols, ensuring that spatial resolution is not affected by code expansion. This modulation method not only overcomes the limitations of the light source's peak power but also effectively improves the system's dynamic range and measurement accuracy, providing a new technical path for long-distance, high-precision distributed sensing.

[0007] As a classic pseudo-random coded sequence, the m-sequence exhibits unique advantages in optical time-domain reflectometry (OTDR) due to its near-ideal autocorrelation properties and simple generation mechanism. Generated through a linear feedback shift register, this sequence possesses a definite periodicity and noise-like statistical characteristics. Its core strength lies in its sharp autocorrelation peak and uniform low sidelobe distribution, enabling accurate extraction of target signals against strong noise backgrounds. In fiber optic sensing systems, the backscattered signal generated after transmission of light pulses modulated with the m-sequence can be significantly improved in signal-to-noise ratio without altering spatial resolution through matched filtering and coherent superposition, while simultaneously avoiding nonlinear effects caused by increasing light source power.

[0008] Compared to classic coding schemes such as aperiodic bipolar complementary Golay coding and Simplex coding, m-sequence only requires acquiring a set of time-domain coded signals from the fiber under test to demodulate the single-pulse response curve of the sensing fiber. Furthermore, considering factors such as the number of sequence switching, time and space complexity, and coding gain, m-sequence presents the optimal solution among numerous coding schemes. Most importantly, because the codewords injected into the sensing fiber by m-sequence are far greater than those in conventional coding, the obtained backscattered signal strength is particularly outstanding. This reduces the dependence on optical amplifiers to a certain extent, indirectly avoiding the "transient effect" that must be considered in coding schemes—the inconsistent amplification capability of optical amplifiers for different time points during the power amplification of the coded sequence. In summary, m-sequence hardware implementation is simple and efficient, with low decoding algorithm complexity, making it particularly suitable for long-distance distributed sensing scenarios with stringent real-time requirements, providing a reliable technical path for high-precision monitoring.

[0009] At this critical stage of industrial sensing technology development, traditional single-pulse detection schemes face fundamental performance bottlenecks when detector sensitivity approaches the quantum limit, system bandwidth is limited by the response characteristics of photoelectric conversion devices, and laser peak power is constrained by the threshold of fiber nonlinear effects. m-sequence coding technology, as a core solution to overcome this "three-limit dilemma," achieves a theoretically high signal-to-noise ratio (SNR) improvement by co-optimizing time-domain coding modulation and digital signal processing while maintaining the system hardware architecture. This dual advantage of coding gain and system compatibility makes the high-quality, highly applicable m-sequence coding scheme a crucial technical solution for achieving performance breakthroughs in optical measurement and sensing systems.

[0010] The purpose of this invention is to overcome the shortcomings of the prior art by providing a light intensity sensing and measurement device based on an m-sequence pulse coding scheme.

[0011] The objective of this invention can be achieved through the following technical solutions:

[0012] A light intensity sensing and measurement device based on an m-sequence pulse coding scheme includes:

[0013] Continuous laser;

[0014] The coded signal generation circuit generates a coded radio frequency signal with m-sequence intensity modulation;

[0015] The optical intensity modulator has its optical input end connected to a continuous laser and its drive signal input end connected to the output end of the encoded signal generation circuit. Based on the encoded radio frequency signal, it outputs a first encoded laser with m-sequence intensity modulation and incident it into the sensor link under test.

[0016] The signal acquisition unit is connected to the coded signal generation circuit and the sensor link under test, respectively, and acquires the backscattered signal of the sensor link under test under the action of the first coded laser, wherein the backscattered signal corresponds to the time interval of the coded radio frequency signal.

[0017] The signal data processing unit is connected to the signal acquisition unit. Based on the scattered signal, it sequentially performs slicing, cumulative averaging, and cross-correlation operations to obtain the light intensity.

[0018] The signal data processing unit is configured to perform the following steps:

[0019] Step S1: Acquire the backscattered signal;

[0020] Step S2: Accumulate and average the acquired backscattered signals to obtain the first signal;

[0021] Step S3: Obtain the coded radio frequency signal corresponding to the backscattered signal, and obtain the bipolar sequence based on the corresponding coded radio frequency signal;

[0022] Step S4: Perform cross-correlation operation on the first signal and the bipolar sequence to obtain the light intensity.

[0023] Step S3 includes:

[0024] Step S3-1: Obtain the coded radio frequency signal corresponding to the backscattered signal;

[0025] Step S3-2: Process the encoded radio frequency signal to obtain a bipolar sequence:

[0026] sig sjx =sig sp ×2-1

[0027] Wherein: sig sjx It is a bipolar sequence, sig sp It is used to encode radio frequency signals.

[0028] The signal acquisition unit is configured to perform the following steps:

[0029] Acquire the raw backscattered signal of the sensor link under test under the action of the first coded laser;

[0030] The backscattered signal is obtained by slicing the original backscattered signal based on the coded radio frequency signal, wherein the time interval of the backscattered signal corresponds to that of the coded radio frequency signal.

[0031] The m-sequence is a 13th-order m-sequence with a length of 8191 and an amplitude range of 0-1.

[0032] The continuous laser is a semiconductor laser.

[0033] The encoded signal generation circuit includes an arbitrary waveform generator and an acousto-optic driver. The output terminal of the arbitrary waveform generator is connected to the acousto-optic driver and the signal acquisition unit, respectively. The acousto-optic driver is connected to the drive signal input terminal of the light intensity modulator.

[0034] The signal acquisition unit includes a photodetector and a high-speed acquisition module. The input terminal of the photodetector is connected to one input terminal of the high-speed acquisition module, the other input terminal of the high-speed acquisition module is connected to the encoded signal generation circuit, and the output terminal is connected to the signal data processing unit.

[0035] The signal data processing unit is a PC.

[0036] The sensor link under test includes single-mode optical fiber.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] 1. By introducing configurable m-sequence intensity coding to replace traditional single-pulse detection, the hardware architecture of the classic optical time-domain reflectometer is retained, resulting in high compatibility.

[0039] 2. Applying m-sequence intensity encoding to light intensity detection provides a stable encoding gain for the scattering signal without sacrificing spatial resolution or detection time, thereby improving the detection accuracy and precision of the sensing system.

[0040] 3. Using high duty cycle m-sequence intensity encoded laser as the detection light source can obtain a higher intensity backscattered signal compared with classic Golay encoding and simplex encoding schemes, so as to realize medium and long distance sensing and monitoring. It greatly eliminates the dependence on optical amplifier and indirectly alleviates the stringent requirements of laser output power.

[0041] 4. The proposed device has a simple hardware system, is easy to operate, and its digital signal processing only includes conventional operations such as matched filtering, which can efficiently monitor the external environment at different distances.

[0042] 5. All optical and electronic equipment involved in the proposed device can be selected from conventional standard devices in the field of optical measurement and sensing technology, and are feasible. Attached Figure Description

[0043] Figure 1 This is a flowchart of the apparatus according to an embodiment of the present invention;

[0044] Figure 2 This is a waveform diagram of a 13th-order m-sequence used in an embodiment of the present invention;

[0045] Figure 3This is a waveform diagram of the drive signal output by the high-speed arbitrary waveform generator in an embodiment of the present invention;

[0046] Figure 4 This refers to the multi-period backscattered signal received by the photodetector in this embodiment of the invention.

[0047] Figure 5 This is a waveform diagram of a 13th-order bipolar m-sequence that has undergone cross-correlation processing with the scattered signal in an embodiment of the present invention;

[0048] Figure 6 This is a diagram illustrating the effect of the optical fiber time-domain response in an embodiment of the present invention;

[0049] The components include: 1. Continuous laser, 2. Arbitrary waveform generator, 3. Acousto-optic driver, 4. Optical intensity modulator, 5. Optical circulator, 6. Sensor link under test, 7. Signal acquisition unit, 7-1. Photodetector, 7-2. High-speed acquisition module, and 8. PC. Detailed Implementation

[0050] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0051] A light intensity sensing and measurement device based on an m-sequence pulse coding scheme, such as Figure 1 As shown, it includes:

[0052] Continuous laser;

[0053] The coded signal generation circuit generates a coded radio frequency signal with m-sequence intensity modulation;

[0054] The optical intensity modulator has its optical input end connected to a continuous laser and its drive signal input end connected to the output end of the encoded signal generation circuit. Based on the encoded radio frequency signal, it outputs a first encoded laser with m-sequence intensity modulation and incident it into the sensor link under test.

[0055] The signal acquisition unit is connected to the coded signal generation circuit and the sensor link under test, respectively, and acquires the backscattered signal of the sensor link under test under the action of the first coded laser, wherein the backscattered signal corresponds to the time interval of the coded radio frequency signal.

[0056] The signal data processing unit is connected to the signal acquisition unit. Based on the scattered signal, it sequentially performs slicing, cumulative averaging, and cross-correlation operations to obtain the light intensity.

[0057] The backscattered signal is generated in the sensing link under test due to the inhomogeneity of the sensing medium; the signal acquisition unit samples and saves the backscattered signal; the signal data processing unit performs matched filtering and digital decoding on the acquired backscattered signal, and finally realizes distributed visual monitoring of optical transmission loss / temperature / strain in the sensing link.

[0058] In this embodiment, the continuous laser is a semiconductor laser with a nominal output frequency of 1550.295nm, a linewidth of 3kHz for the output continuous light, and an output power of 50mW.

[0059] The signal data processing unit is a PC.

[0060] The optical intensity modulator is a 1550nm fiber acousto-optic modulator with a nominal acousto-optic crystal frequency shift of 200MHz, an extinction ratio greater than 50dB, and an insertion loss of less than 3dB. The fiber acousto-optic modulator can be paired with a matching acousto-optic driver, which is nominally capable of outputting a radio frequency signal with a stability better than 100ppm when using a digital modulation signal input. Since this experiment uses m-sequence intensity modulation, the m-sequence code is simply used as a digital modulation signal, input to the acousto-optic driver via a high-speed arbitrary waveform generator, and then the acousto-optic driver provides a high-intensity radio frequency signal of 200MHz to drive the acousto-optic modulator, thereby generating the m-sequence intensity modulated coded laser. In this embodiment, a 13th-order m-sequence is used, with a sequence length of 2... 13 -1 = 8191, the sequence amplitude is either 0 or 1, and its waveform is as follows: Figure 2 As shown.

[0061] The encoded signal generation circuit includes an arbitrary waveform generator and an acousto-optic driver. The output of the arbitrary waveform generator is connected to both the acousto-optic driver and the signal acquisition unit. The acousto-optic driver is connected to the drive signal input of the light intensity modulator. The encoded signal generation circuit uses a high-speed arbitrary waveform generator with a nominal sampling rate of 1GSa / s, an analog bandwidth of 120MHz, and a storage capacity of 64MSa. It has two independent analog output channels and one synchronous digital trigger channel. One of the independent output channels of the arbitrary waveform generator generates an m-sequence intensity modulated radio frequency waveform, which is then used as a drive signal input to the radio frequency input of the acousto-optic driver. The digital trigger channel generates a trigger signal, which is input to the trigger terminal of the signal acquisition unit to achieve synchronous signal acquisition. At a sampling rate of 1GSa / s, the waveform of the drive signal is shown below. Figure 3 As shown, the sequence length is 50 × 8191 × 3 = 1,228,650. The 50 points correspond to a spatial resolution of 5m in the system, 8191 corresponds to a 13th-order m sequence length, and 3 refers to the minimum number of trigger cycles. The sequence carries a 200MHz carrier frequency, which is perfectly matched to the acousto-optic driver, and the sequence amplitude ranges from -1 to 1.

[0062] The sensor link under test uses G.652.D single-mode fiber with a nominal length of 25.1 km and a loss of 0.183 dB / km at 1550 nm. Encoded lasers with m-sequence intensity modulation are injected into the single-mode fiber under test. Backscattering occurs due to the non-uniform refractive index distribution in the fiber core and is received by the signal acquisition unit.

[0063] The signal acquisition unit includes a photodetector and a high-speed acquisition module. The input of the photodetector is connected to one input of the high-speed acquisition module, and the other input of the high-speed acquisition module is connected to the encoded signal generation circuit. The output is connected to the signal data processing unit. The photodetector is an InGaAs type photodetector with a nominal 3dB bandwidth of DC-200MHz and a cross-group gain of 10kV / W@1550nm. The photodetector receives the backscattered light signal from the optical fiber under test and converts it into an electrical signal, which is then transmitted to the high-speed acquisition module. The high-speed acquisition module uses a programmable high-speed acquisition card with a nominal analog bandwidth of 400MHz, a sampling rate of 1GS / s@8-bit resolution, 500MS / s@12-bit resolution, and 512MSa of memory. Figure 4 The diagram illustrates a portion of the multi-period backscattered signal received by the photodetector, representing the intensity superposition of the pulse-coded fiber time-domain response. A single period of the scattered signal is determined by the driving signal, i.e., the aforementioned 1228650 points; the total sequence length = single period length × cumulative averaging count. As shown in the diagram, due to the weak backscattering intensity, the periodic signal without cumulative averaging is almost submerged in noise. The high-speed acquisition card synchronously acquires the fiber backscattered signal based on the trigger signal period of an arbitrary waveform generator. The acquisition length and number of acquisitions can be modified according to actual needs. In this embodiment, each chip is 50 ns (corresponding to a system spatial resolution of 5 m), the single trigger acquisition period is 1228650 ns (this period is the duration of the first and last repetitions of a 13th-order m-sequence three times), and the total cumulative averaging count is 400.

[0064] Based on this, in this embodiment, the signal acquisition unit is configured to perform the following steps:

[0065] Acquire the raw backscattered signal of the sensor link under test under the action of the first coded laser;

[0066] The backscattered signal is obtained by slicing the original backscattered signal based on the coded radio frequency signal, where the time interval of the backscattered signal corresponds to that of the coded radio frequency signal.

[0067] The signal data processing unit is configured to perform the following steps:

[0068] Step S1: Acquire the backscattered signal;

[0069] Step S2: Accumulate and average the acquired backscattered signal to obtain the first signal;

[0070] Step S3: Obtain the coded radio frequency signal corresponding to the backscattered signal, and obtain the bipolar sequence based on the corresponding coded radio frequency signal, including:

[0071] Step S3-1: Obtain the coded radio frequency signal corresponding to the backscattered signal;

[0072] Step S3-2: Process the encoded radio frequency signal to obtain a bipolar sequence:

[0073] sig sjx =sig sp ×2-1

[0074] Where: sig sjx It is a bipolar sequence, sig sp It is used to encode radio frequency signals.

[0075] The signal data processing unit uses a PC. First, it performs matched filtering on the fiber backscattered signal acquired by the high-speed acquisition card to reduce interference from other frequency band noise on the effective signal. In this embodiment, the Rayleigh scattering signal is filtered out to monitor optical transmission loss and breakpoints in the sensing link. Next, the filtered signal is modulated with a bipolar sequence of m-sequence intensity modulation waveforms preset by a high-speed arbitrary waveform generator, such as... Figure 5 As shown, the waveform of the 13th-order bipolar m-sequence is obtained from the unipolar sequence ×2-1, and will be used as the decoded waveform and the scattered signal for cross-correlation operation. The duration of a single chip in the sequence corresponds to a spatial resolution of 50 ns, the total sequence length is 50 × 8191 = 409550, and the sequence amplitude is from -1 to 1. The optical intensity attenuation status of the entire optical fiber link is obtained through cross-correlation operation, and finally, real-time distributed monitoring of optical transmission loss and breakpoints in the sensing link can be realized.

[0076] Step S4: Perform cross-correlation operation on the first signal and the bipolar sequence to obtain the light intensity.

[0077] An embodiment of the present invention provides a light intensity sensing and measurement method based on an m-sequence pulse coding scheme. Figure 6 This paper presents the Rayleigh backscattered signal attenuation after 400 averages over a 25.1 km single-mode fiber under test, with a spatial resolution of 5 m and without an optical amplifier, at a specific detection time. This data reflects the real-time distributed monitoring of optical transmission loss and breakpoints in the tested link. Figure 6 The horizontal axis represents the length of the single-mode fiber, and the vertical axis represents the intensity of the back Rayleigh scattering light signal.

[0078] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

Claims

1. A light intensity sensing and measurement device based on an m-sequence pulse coding scheme, characterized in that, include: Continuous laser; The coded signal generation circuit generates a coded radio frequency signal with m-sequence intensity modulation; The optical intensity modulator has its optical input end connected to a continuous laser and its drive signal input end connected to the output end of the encoded signal generation circuit. Based on the encoded radio frequency signal, it outputs a first encoded laser with m-sequence intensity modulation and incident it into the sensor link under test. The signal acquisition unit is connected to the coded signal generation circuit and the sensor link under test, respectively, and acquires the backscattered signal of the sensor link under test under the action of the first coded laser, wherein the backscattered signal corresponds to the time interval of the coded radio frequency signal. The signal data processing unit, connected to the signal acquisition unit, obtains the light intensity based on the scattered signal by sequentially performing slicing, cumulative averaging, and cross-correlation operations.

2. The light intensity sensing and measurement device based on the m-sequence pulse coding scheme according to claim 1, characterized in that, The signal data processing unit is configured to perform the following steps: Step S1: Acquire the backscattered signal; Step S2: Accumulate and average the acquired backscattered signal to obtain the first signal; Step S3: Obtain the coded radio frequency signal corresponding to the backscattered signal, and obtain the bipolar sequence based on the corresponding coded radio frequency signal; Step S4: Perform cross-correlation operation on the first signal and the bipolar sequence to obtain the light intensity.

3. The light intensity sensing and measurement device based on the m-sequence pulse coding scheme according to claim 2, characterized in that, Step S3 includes: Step S3-1: Obtain the coded radio frequency signal corresponding to the backscattered signal; Step S3-2: Process the encoded radio frequency signal to obtain a bipolar sequence: say sjx =say sp ×2-1 Wherein: sig sjx It is a bipolar sequence, sig sp It is used to encode radio frequency signals.

4. The light intensity sensing and measurement device based on the m-sequence pulse coding scheme according to claim 1, characterized in that, The signal acquisition unit is configured to perform the following steps: Acquire the raw backscattered signal of the sensor link under test under the action of the first coded laser; The backscattered signal is obtained by slicing the original backscattered signal based on the coded radio frequency signal, wherein the time interval of the backscattered signal corresponds to that of the coded radio frequency signal.

5. The light intensity sensing and measurement device based on the m-sequence pulse coding scheme according to claim 1, characterized in that, The m-sequence is a 13th-order m-sequence with a length of 8191 and an amplitude range of 0-1.

6. The light intensity sensing and measurement device based on the m-sequence pulse coding scheme according to claim 1, characterized in that, The continuous laser is a semiconductor laser.

7. The light intensity sensing and measurement device based on the m-sequence pulse coding scheme according to claim 1, characterized in that, The encoded signal generation circuit includes an arbitrary waveform generator and an acousto-optic driver. The output terminal of the arbitrary waveform generator is connected to the acousto-optic driver and the signal acquisition unit, respectively. The acousto-optic driver is connected to the drive signal input terminal of the light intensity modulator.

8. The light intensity sensing and measurement device based on the m-sequence pulse coding scheme according to claim 1, characterized in that, The signal acquisition unit includes a photodetector and a high-speed acquisition module. The input terminal of the photodetector is connected to one input terminal of the high-speed acquisition module, the other input terminal of the high-speed acquisition module is connected to the encoded signal generation circuit, and the output terminal is connected to the signal data processing unit.

9. A light intensity sensing and measurement device based on an m-sequence pulse coding scheme according to claim 1, characterized in that, The signal data processing unit is a PC.

10. A light intensity sensing and measurement device based on an m-sequence pulse coding scheme according to claim 1, characterized in that, The sensor link under test includes single-mode optical fiber.

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