A transceiver integrated laser coherent detection indoor simulation device and method

Abstract

This application discloses an indoor simulation device and method for integrated transceiver laser coherent detection, comprising: a laser seed source emitting laser light to a first beam splitter; the first beam splitter splitting the laser light into two paths, one of which passes sequentially through a first optical modulator and is incident on a simulated circulator, and the other path is incident on a first beam combiner; a simulated circulator receiving laser light from a second optical amplifier to detect the target, its emitted laser light passing through the first beam combiner, the first beam combiner being connected to a signal acquisition and processing device to acquire coherent signal characteristics. The device of this application can simulate interference signals introduced by the circulator in long-distance integrated transceiver laser coherent ranging in a laboratory setting, and separate the leakage light interference signal from the target echo light from the light propagation path, achieving separate control of the return light signal and the leakage light signal.

Description

Technical Field

[0001] This application relates to the field of laser coherent ranging technology, and in particular to an indoor simulation device and method for laser coherent detection that integrates transceiver and receiver. Background Technology

[0002] A basic transceiver-integrated laser coherent ranging system consists of a laser source, beam splitter, optical modulator, optical amplifier, circulator, single lens, beam combiner, detector, and signal acquisition and processing unit. The laser emitted by the laser source is split into two beams by the beam splitter: one serves as the local oscillator beam, and the other as the signal beam. The signal beam is modulated by the optical modulator to form a transmission pulse signal, which is then amplified and injected from end 1 of the circulator and exited from end 2. The echo signal enters from the same lens at end 2 of the circulator, passes through end 3 of the circulator, is amplified, and then combined with the local oscillator signal beam. The detector detects the combined beam signal, and the signal acquisition and processing unit analyzes the detected signal.

[0003] In a transceiver integrated laser coherent ranging system, the circulator is a key component for achieving coaxial transmission and reception. However, due to insufficient optical isolation of the circulator, a portion of the optical signal incident from port 1 of the circulator leaks to port 3. This results in the detector being able to detect the signal light at the moment of pulse emission, causing significant impact during close-range detection.

[0004] When simulating a transceiver integrated ranging system indoors, using a delayed fiber connected to the circulator's third end to simulate a long-distance echo signal, even without target illumination, the leaked light will still pass through the fiber delay line and reach the detector after a corresponding delay, causing the detector to detect this portion of the signal. A 1-microsecond pulse width corresponds to approximately 150 meters of actual spatial distance. The limited indoor space cannot accommodate a straight-line length of several hundred meters. Therefore, when using a pulse signal with a pulse width of several microseconds for target illumination, the returned signal light will be submerged in the leaked light, making target resolution impossible and thus failing to achieve the indoor simulation purpose of a long-distance transceiver integrated laser ranging system. Summary of the Invention

[0005] This application provides an indoor simulation device and method for a transceiver integrated laser coherent detection system. It is used to simulate the interference signal caused by the circulator in a transceiver integrated long-distance laser coherent ranging system in the laboratory, and to separate the leakage light interference signal from the target echo light from the light propagation path. This allows for the separate control of the return light signal and the leakage light signal, and explores the impact of the two on the final signal processing result. In particular, it addresses the application scenarios such as echo signal processing with Doppler frequency shift and distance ambiguity.

[0006] This application provides an integrated transceiver laser coherent detection indoor simulation device, comprising:

[0007] A laser seed source emits a laser beam to the first beam splitter;

[0008] The first beam splitter is used to split the laser into two paths. One path passes through the first optical modulator and is then incident on the simulated circulator, while the other path is incident on the first beam combiner.

[0009] A simulated circulator is used to receive laser light from the second optical amplifier to detect the target under test. Its emitted laser light passes through the first beam combiner, which is connected to a signal acquisition and processing device to acquire coherent signal features.

[0010] Optionally, the simulation device includes a first optical switch, an optical circulator, a second beam splitter, a first attenuator, a second attenuator, a delay fiber, a polarizer, a second beam combiner, and a second optical switch, wherein:

[0011] The first optical switch has one end connected to the output optical path of the first optical modulator, and the other end used to switch between the simulated optical circulator and the second beam splitter.

[0012] The second beam splitter has one output connected to the transmitting lens and another output connected to the attenuator, which is connected to the second beam combiner.

[0013] After receiving the echo signal from the target under test, the receiving lens passes sequentially through the second optical modulator, the delayed optical fiber, the polarizer, and the second attenuator before being incident on the second beam combiner.

[0014] The second optical switch has one end used to switch between the output of the second beam combiner and the output of the optical circulator, and the other end outputs an optical signal to the first beam combiner.

[0015] Optionally, the simulated circulator further includes a first adjustable ramp pulse stretcher and a second adjustable ramp pulse stretcher, wherein the first adjustable ramp pulse stretcher is disposed between the second beam splitter and the first attenuator, and the second adjustable ramp pulse stretcher is disposed between the second optical modulator and the delay fiber.

[0016] Optionally, a first optical amplifier and a second optical amplifier are respectively provided on both sides of the first optical modulator, wherein the second optical amplifier is connected to one end of the first optical switch.

[0017] Optionally, it also includes an optical signal modulation device, which is connected to the other end of the second optical switch, and the output of the optical signal modulation device is connected to the first beam combiner through a third optical amplifier.

[0018] This application also proposes an indoor simulation method for a transceiver integrated laser coherent detection system, implemented based on the aforementioned indoor simulation device for a transceiver integrated laser coherent detection system, comprising the following steps:

[0019] In the indoor simulation, the first optical switch is connected to the optical circulator being simulated, and the second optical switch is connected to the output of the optical circulator;

[0020] Initiate laser coherent detection, keep the input parameters constant, and record the characteristics of the first coherent signal through the signal acquisition and processing device;

[0021] The first optical switch is switched to the second beam splitter, the second optical switch is switched to the second beam combiner, the receiving lens is blocked, the input parameters are kept constant, and the optical attenuator is adjusted so that the signal acquisition and processing device also records the first coherent signal characteristics.

[0022] Optionally, it also includes opening the receiving lens, aligning the transmitting and receiving lenses with the target under test, and setting a second optical modulator, delay fiber, and polarizer as needed.

[0023] The laser coherent detection indoor simulation device of this application embodiment can simulate the interference signal brought by the circulator in the long-distance laser coherent ranging of the integrated transceiver in the laboratory, and separate the leakage light interference signal from the target echo light from the light propagation path, realize the separate control of the return light signal and the leakage light signal, and explore the influence of the two on the final signal processing result, especially for the application of echo signal processing with Doppler frequency shift, distance ambiguity problem, etc.

[0024] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0025] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0026] Figure 1 This is an example of the overall structure of the indoor simulation device for integrated transceiver laser coherent detection according to an embodiment of this application;

[0027] Figure 2 This is another structural example of the indoor simulation device for integrated transceiver laser coherent detection according to the embodiments of this application;

[0028] Figure 3 This is an example of a delay time relationship in an application embodiment of this application;

[0029] Figure 4 This is another example of a delay time relationship in an embodiment of this application. Detailed Implementation

[0030] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0031] This application provides an integrated transceiver laser coherent detection indoor simulation device, such as... Figure 1 As shown, it includes:

[0032] A laser seed source emits laser light to a first beam splitter. In some embodiments, a first optical amplifier and a second optical amplifier are respectively disposed on both sides of the first optical modulator, wherein the second optical amplifier is connected to one end of the first optical switch.

[0033] The first beam splitter is used to split the laser into two paths. One path passes through the first optical modulator and is then incident on the analog circulator, while the other path is incident on the first beam combiner.

[0034] A simulated circulator is used to receive laser light from the second optical amplifier to detect the target under test. Its emitted laser light passes through the first beam combiner, which is connected to a signal acquisition and processing device to acquire coherent signal features.

[0035] In some embodiments, an optical signal modulation device is further included, which is connected to the other end of the second optical switch, and the output of the optical signal modulation device is connected to the first beam combiner via a third optical amplifier. In some specific examples, the analog device can be added after the second optical switch and before the third optical amplifier to achieve special processing of the leaked light at ends 1-3 of the circulator.

[0036] like Figure 1As shown, the apparatus in this embodiment includes a laser seed source, a beam splitter, a beam combiner, an optical amplifier, an optical modulator, a simulated circulator, an optical switch, a tunable pulse stretcher, an attenuator, a delay fiber, a polarization controller, a detector, and a signal acquisition processor. In this embodiment, the laser seed source, the first beam splitter, the first beam combiner, the first, second, and third optical amplifiers, the detector, and the signal acquisition processor are basic components used in laser coherent detection, primarily responsible for generating the local oscillator signal and the transmitted signal, as well as coherently calculating the echo light and the local oscillator light. The first, second, and third optical amplifiers and the optical signal modulation device are optional components of the coherent detection system.

[0037] The simulation device in this application embodiment can simulate the interference signal introduced by the circulator in a transceiver-integrated long-distance laser coherent ranging system in the laboratory. It separates the leaked light interference signal from the target echo light along the optical propagation path, enabling separate control of the return and leaked light signals. This allows for the investigation of their impact on the final signal processing result, and is particularly suitable for applications such as processing echo signals with Doppler frequency shift and distance ambiguity problems. The introduction of the optical signal modulation device enables the processing of optical signals in different time domains, especially the blocking of leaked light signals.

[0038] In some implementations, such as Figure 1 As shown, the simulated circulator includes a first optical switch, an optical circulator, a second beam splitter, a first attenuator, a second attenuator, a delay fiber, a polarizer, a second beam combiner, and a second optical switch, wherein:

[0039] The first optical switch has one end connected to the output optical path of the first optical modulator, and the other end used to switch between the optical circulator and the second beam splitter.

[0040] The second beam splitter has one output connected to the transmitting lens and another output connected to the first attenuator, which is connected to the second beam combiner.

[0041] After receiving the echo signal from the target under test, the receiving lens passes sequentially through the second optical modulator, the delayed optical fiber, the polarizer, and the second attenuator before being incident on the second beam combiner.

[0042] The second optical switch has one end used to switch between the output of the second beam combiner and the output of the optical circulator, and the other end outputs an optical signal to the first beam combiner.

[0043] The optical circulator, a key component for achieving integrated transceiver operation, is simulated using a combination of beam splitter 2, attenuator 1, and beam combiner 2 to mimic its optical leakage. In the indoor simulation, the first optical switch is connected to terminal A, and the second optical switch to terminal C. The laser coherent detection system is activated, maintaining constant input parameters, and the coherent signal characteristics (M) obtained by the detector and signal acquisition processor are recorded. The first optical switch is then switched to terminal B, and the second optical switch to terminal D. The optical signal output from terminal B enters the second beam splitter; part of it serves as the simulated circulator leakage signal, and the other part illuminates the target through the transmitting lens. The receiving lens is blocked, and the optical attenuator is adjusted to ensure that, under the condition of constant input parameters of the laser coherent detection system, the signal characteristics obtained by the signal processor are also coherent signal characteristics (M).

[0044] like Figure 2 As shown, the simulated circulator also includes a first adjustable slope pulse stretcher and a second adjustable slope pulse stretcher, wherein the first adjustable slope pulse stretcher is disposed between the second beam splitter and the first attenuator, and the second adjustable slope pulse stretcher is disposed between the second optical modulator and the delay fiber. The adjustable pulse stretcher 1 is used to simulate the time stretching of the echo pulse at the circulator 3 end caused by atmospheric scattering and other factors at extremely close range.

[0045] In some specific examples, such as Figure 3 As shown, optical amplifier 2 emits an optical pulse P1 with a pulse width of t0 (nanoseconds or microseconds) at time 0. Under laboratory conditions, a delay fiber is added at the circulator 3 end to extend the target distance. Due to light leakage from the circulator 1 to 3 ends, the emitted optical pulse P1 will arrive at the receiving end as optical pulse P2 after a delay time t1 corresponding to the length of the delay fiber (the delay time corresponding to kilometers is hundreds of microseconds).

[0046] like Figure 4 As shown, since the indoor distance is less than the distance corresponding to the transmitted pulse width t0 (on the order of hundreds of meters), the delay time between the indoor target echo P3 and the occurrence time 0 is t1+t2; t2 corresponds to the round-trip distance inside the room, which is generally less than t0. This causes pulses P2 and P3 to partially overlap in time. During detection, what is detected is the overlapping wide pulse P4, making it impossible to separate the circulator leakage light pulse and the target return light pulse in time.

[0047] Especially when performing integrated transceiver ranging at close range in atmospheric conditions, circulator light leakage, specular reflection, and near-range atmospheric scattering can broaden the echo pulse, such as pulse P6. During detection, signal lights P2 and P6 together form a wide pulse P7, greatly increasing the difficulty of separating and detecting P2 and P6.

[0048] The indoor simulation device of this application splits the emitted pulsed light signal into two branches. One branch simulates a circulator. By comparing the characteristics (pulse width, intensity, etc.) of the simulated circulator light signal, the light pulses in this branch (pulses P5 and P8) are modulated using an attenuator and a tunable pulse stretcher, so that the modulated light pulses match the characteristics of the simulated circulator detection signal. The other branch connects to an optical fiber delay line to simulate long-distance pulse echoes (pulses P3 and P6). Optionally, a tunable pulse stretcher, attenuator, and polarizer can be added to simulate atmospheric echo characteristics. In this way, during simulation experiments, on the one hand, echo pulses containing leakage light signals can be processed to analyze the impact of leakage light signals on distance detection; on the other hand, an experimental platform is provided for how laser rangefinders handle leakage light.

[0049] The laser coherent detection indoor simulation device of this application embodiment can simulate the interference signal brought by the circulator in the long-distance laser coherent ranging of the integrated transceiver in the laboratory, and separate the leakage light interference signal from the target echo light from the light propagation path, realize the separate control of the return light signal and the leakage light signal, and explore the influence of the two on the final signal processing result, especially for the application of echo signal processing with Doppler frequency shift, distance ambiguity problem, etc.

[0050] This application also proposes an indoor simulation method for a transceiver integrated laser coherent detection system, implemented based on the aforementioned indoor simulation device for a transceiver integrated laser coherent detection system, comprising the following steps:

[0051] In the indoor simulation, the first optical switch is connected to the optical circulator, and the second optical switch is connected to the output of the optical circulator;

[0052] Initiate laser coherent detection, keep the input parameters constant, and record the characteristics of the first coherent signal through the signal acquisition and processing device;

[0053] The first optical switch is switched to the second beam splitter, the second optical switch is switched to the second beam combiner, the receiving lens is blocked, the input parameters are kept constant, and the optical attenuator is adjusted so that the signal acquisition and processing device also records the first coherent signal characteristics.

[0054] In some implementations, the receiving lens is opened, the transmitting and receiving lenses are aligned with the target under test, and a second optical modulator, delay fiber, and polarizer are set up as needed.

[0055] In the specific indoor simulation application, the first optical switch is first connected to terminal A, and the second optical switch is connected to terminal C. The laser coherent detection system is started, and the input parameters are kept constant. The coherent signal characteristics obtained by the detector and signal acquisition processor are recorded as M. The first optical switch is then switched to terminal B, and the second optical switch is switched to terminal D. The optical signal output from terminal B enters the second beam splitter, with part of it used as the optical signal simulating the leakage of the circulator, and the other part used to illuminate the target through the transmitting lens. The receiving lens is blocked, and the optical attenuator is adjusted so that, under the condition of constant input parameters of the laser coherent detection system, the signal characteristics obtained by the signal processor are also coherent signal characteristics M.

[0056] Next, the receiving lens is removed to allow it to receive the echo light from the target. The echo light signal passes through a second optical modulator (optional), a delay fiber, a polarization controller, and an attenuator before being combined with the attenuated transmitted light signal and entering from the D end of the second optical switch. The second optical modulator simulates the Doppler frequency shift caused by a moving target, the delay fiber delays the return light signal to simulate long-distance transmission, the polarization controller simulates the polarization state of the echo light signal, and the attenuator simulates the attenuation of the light signal at different intensities in the application environment.

[0057] In this embodiment, firstly, for different coherent characteristic signals M achieved by different performance indicators of different optical circulators, attenuator 1 can be used for modulation to realize differentiated simulation of optical circulators.

[0058] Secondly, the device enables separate control of two signals: one is the modulated optical signal (i.e., the leaked optical signal) generated by the optical modulator 1, and the other is the simulated echo signal of a distant target, realizing the simulation of a distant echo signal using a delay line under near-target conditions.

[0059] Third, a tunable pulse stretcher 1 was used to simulate the pulse time stretching of the echo pulse at the circulator 3 end caused by atmospheric scattering at extremely close distances.

[0060] Fourth, the combined use of optical modulator 2, tunable pulse stretcher 2, delay fiber, polarizer and attenuator 2 enables control of echo signal frequency, pulse width, arrival time, polarization and power, simulating the impact of leaked light signal and echo signal on signal detection and data acquisition and processing in real environment. It can serve as an experimental platform for the design and implementation of transceiver integrated laser coherent detection hardware, waveform design and algorithm design.

[0061] It should be noted that, in the embodiments of this application, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0062] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0063] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal (which may be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0064] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims. All of these forms are within the protection scope of this application.

Claims

1. A transceiver integrated indoor simulation device for laser coherent detection, characterized in that, include: A laser seed source emits a laser beam to the first beam splitter; The first beam splitter is used to split the laser into two paths. One path passes through the first optical modulator and is then incident on the analog circulator. The other path is incident on the first beam combiner. The first optical modulator is provided with a first optical amplifier and a second optical amplifier on its two sides, respectively. A simulated circulator is used to receive laser light from the second optical amplifier to detect the target under test. Its emitted laser light passes through the first beam combiner, which is connected to a signal acquisition and processing device to acquire coherent signal features. The simulated circulator includes a first optical switch, an optical circulator, a second beam splitter, a first attenuator, a second attenuator, a delay fiber, a polarizer, a second beam combiner, and a second optical switch, wherein: The first optical switch has one end connected to the output optical path of the first optical modulator, and the other end used to switch between the optical circulator and the second beam splitter. The second beam splitter has one output connected to the transmitting lens and another output connected to the first attenuator, which is connected to the second beam combiner. After receiving the echo signal from the target under test, the receiving lens passes sequentially through the second optical modulator, the delayed optical fiber, the polarizer, and the second attenuator before being incident on the second beam combiner. The second optical switch has one end used to switch between the output of the second beam combiner and the output of the optical circulator, and the other end outputs an optical signal to the first beam combiner. The second optical amplifier is connected to one end of the first optical switch.

2. The indoor simulation device for integrated laser coherent detection as described in claim 1, characterized in that, The analog circulator also includes a first adjustable ramp pulse stretcher and a second adjustable ramp pulse stretcher, wherein the first adjustable ramp pulse stretcher is disposed between the second beam splitter and the first attenuator, and the second adjustable ramp pulse stretcher is disposed between the second optical modulator and the delay fiber.

3. The indoor simulation device for integrated laser coherent detection as described in claim 1, characterized in that, It also includes an optical signal modulation device, which is connected to the other end of the second optical switch, and the output of the optical signal modulation device is connected to the first beam combiner through a third optical amplifier.

4. A transceiver integrated laser coherent detection indoor simulation method, implemented based on the transceiver integrated laser coherent detection indoor simulation device as described in claim 1 or 2, comprising the following steps: In the indoor simulation, the first optical switch is connected to the optical circulator, and the second optical switch is connected to the output of the optical circulator; Initiate laser coherent detection, keep the input parameters constant, and record the characteristics of the first coherent signal through the signal acquisition and processing device; The first optical switch is switched to the second beam splitter, the second optical switch is switched to the second beam combiner, the receiving lens is blocked, the input parameters are kept constant, and the optical attenuator is adjusted so that the signal acquisition and processing device also records the first coherent signal characteristics.

5. The indoor simulation method for integrated transceiver laser coherent detection as described in claim 4, characterized in that, It also includes opening the receiving lens, aligning the transmitting and receiving lenses with the target to be tested, and then combining the echo light signal with the attenuated transmitted light signal after passing through the second optical modulator, delay fiber, polarizer, and attenuator, and entering from one end of the second optical switch.

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