A test system for multi-wavelength pulsed lasers

Abstract

The present invention describes a test system for multi-wavelength pulsed lasers. The test system primarily includes a power supply module, a multi-wavelength pulsed laser, a temperature control module, a laser test platform, a main control module, an alarm module, and a data processing module. Through the rational design of the test scheme and the selection of test components, real-time testing, data processing, and instant feedback can be performed for performance parameters such as laser energy, polarization degree, pulse width, center wavelength, divergence angle, overlap, and directivity. This improves the integration and reliability of the test platform, reduces test errors, and fully verifies the operating life of the laser. While suitable for testing multi-wavelength pulsed lasers, this solution is also suitable for performance testing of other single- and dual-wavelength pulsed lasers, demonstrating its broad applicability.

Description

Technical Field

[0001] The invention belongs to the technical field of laser testing and relates to a testing system for multi-wavelength pulse lasers. Background Art

[0002] Atmospheric sounding lidar is the main payload of atmospheric environment monitoring satellites. The laser, as the core unit of atmospheric sounding lidar, is required to provide a multi-wavelength pulse laser light source with high energy, narrow linewidth, and high polarization contrast. It places strict requirements on the laser output performance parameters and working life. It is urgent to propose a test scheme for multi-wavelength pulse lasers to conduct accurate, complete, and full-process tests on various performance parameters of the laser to fully verify the reliability of the laser's on-orbit operation.

[0003] Traditional laser test systems have incomplete test parameters, complex optical path debugging, unclear test component parameters and debugging status, and are unable to perform real-time monitoring and instant feedback on laser parameters. This leads to complex test platform construction, large test errors, and the inability to perform long-term stable testing. In order to improve the stability and reliability of the laser test system, it is necessary to build a highly integrated and reliable multi-wavelength laser test system. Summary of the Invention

[0004] To solve the above problems, the purpose of the present invention is to provide a test system for multi-wavelength pulsed lasers. Through the rational design of the test scheme and the rational selection of test components, comprehensive testing and instant feedback can be performed on the laser output performance parameters, thereby improving the reliability of the test platform, reducing test errors, and fully verifying the working life of the laser.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A test system for multi-wavelength pulsed lasers, comprising:

[0007] a power supply module, electrically connected to the multi-wavelength pulse laser, for supplying power to the multi-wavelength pulse laser;

[0008] A temperature control module is electrically connected to the power supply module and the multi-wavelength pulse laser, respectively, for controlling the temperature of the power supply module and the multi-wavelength pulse laser, and transmitting temperature control data to the main control module to ensure a stable state throughout the test process;

[0009] A laser testing platform, configured to receive the output laser pulses of the multi-wavelength pulse laser to perform performance parameter testing and transmit the test results to a main control module;

[0010] The main control module is used to collect and process the internal telemetry parameters and external test parameters of the multi-wavelength pulse laser. The external test includes directivity test, divergence angle and coincidence test, energy and polarization test, and pulse width and center wavelength test.

[0011] Furthermore, it includes: the laser test platform includes a first reflector, a twelfth reflector, a collimator and a first image sensor placed in sequence along the optical path for directivity testing; a second reflector, an off-axis telescope and a second image sensor for divergence angle and coincidence testing; multiple multi-wavelength reflectors, single-wavelength reflectors, a beam expander, an energy meter and a polarization testing device for energy and polarization testing; multiple filters, coupling mirrors, optical fiber beam splitters, wavelength meters and photodetectors for pulse width and center wavelength testing.

[0012] The main control module is equipped with a control unit and a data transmission unit. The control unit is used to transmit laser control commands to the power supply module to control the working state of the multi-wavelength pulse laser; the data transmission unit is used to collect and transmit internal telemetry and external test data of the multi-wavelength pulse laser to achieve real-time monitoring of the internal state of the multi-wavelength pulse laser.

[0013] The main control module also includes an alarm module. When the collected data exceeds the allowable range, the current status is recorded. The alarm module then issues an alarm and controls the power supply module according to the abnormal status of the multi-wavelength pulse laser to achieve control of the working status of the multi-wavelength pulse laser and ensure the safety of the test system.

[0014] The main control module also includes a data processing module, which is used to store, process and display in real time the collected internal telemetry and external test data of the multi-wavelength pulse laser.

[0015] The temperature control module includes a water-cooling circulation board and a water chiller. The water-cooling circulation board is used to control the temperature and dissipate heat of the power supply module and the multi-wavelength pulse laser, and transmit the temperature control data to the main control module to ensure the stability of the entire test process.

[0016] The central wavelength is obtained by splitting the output laser of the multi-wavelength pulse laser by wavelength through the test optical path, and coupling part of the energy to the optical fiber beam splitter through the coupling mirror to transmit it to the wavelength meter to collect data and transmit it to the main control module for data processing and storage.

[0017] The laser directivity is achieved by injecting part of the laser energy output by the multi-wavelength pulse laser into the collimator through the test optical path and collecting the light spot through the image sensor and transmitting it to the main control module, respectively reading the centroid coordinates ([Xλn, Yλn]) of each wavelength laser pulse and the centroid coordinates ([x, y]) of the multi-wavelength pulse laser's own reference mirror. The directivity test results are: The image sensor needs to be placed at the focal plane of the collimator, and F is the focal length of the collimator.

[0018] The polarization contrast is obtained by splitting the output laser of the multi-wavelength pulse laser by wavelength through a test optical path and injecting part of the energy into a polarization test device. The polarization test device is composed of a half-wave plate and multiple polarization splitting elements. The multiple polarization splitting elements are used to improve the polarization test accuracy. The energy meter collects the P light and S light energy obtained by the polarization test device and transmits them to the main control module to calculate the polarization contrast of the multi-wavelength pulse laser.

[0019] Wherein, EP and ES are the P light and S light energies.

[0020] Compared with the prior art, the present invention has the following beneficial results:

[0021] 1. The present invention uses a set of test platforms to perform real-time testing of various performance parameters output by multi-wavelength pulsed lasers, reducing the system complexity of independent testing of single parameters. In particular, small signal performance parameters such as pulse width, laser wavelength, and line width are tested using fiber-coupled spatial laser pulses, which simplifies the test optical path, improves test efficiency, and enhances the stability and reliability of the test system.

[0022] 2. The measuring equipment used in the present invention has all passed metrology, and the optical components have all undergone surface screening and transmittance calibration, which reduces the error introduced by the uncertainty of the test equipment. At the same time, the entire test platform is fixed on an optical platform, thereby ensuring the reliability of the test system and reducing the error of the test system.

[0023] 3. The laser testing platform proposed in the present invention has a real-time acquisition and alarm feedback module for laser performance parameters, which can store and analyze the laser performance parameters in real time during the entire test process. At the same time, it can also immediately shut down the laser when an abnormality occurs, ensuring the safety of the laser testing process.

[0024] 4. The measurement method adopted by the present invention is particularly suitable for testing multi-wavelength pulse lasers, and is also suitable for performance testing of other single-wavelength and dual-wavelength pulse lasers, and has wide applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 3 is a structural block diagram of a test system for multi-wavelength pulsed lasers provided by an embodiment of the present invention, wherein optical paths, circuits, and water transmission are represented by solid lines, and data and signal transmission are represented by dotted lines.

[0026] Figure 2 Schematic diagram of a test platform for multi-wavelength pulsed lasers provided by an embodiment of the present invention, wherein the multi-wavelengths take three wavelengths as an example, namely 1064nm, 532nm and 1572nm. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to better understand the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0028] like Figure 1 As shown, a block diagram of a multi-wavelength laser testing system includes a power supply module 10, a multi-wavelength pulse laser 20, a temperature control module 30, a laser testing platform 40, a main control module 50, an alarm module 60, and a data processing module 70. The multi-wavelength laser testing system operates as follows: the temperature control module 30 is used to control the temperature of the power supply module 10 and the multi-wavelength pulse laser 20, and transmits temperature control data to the main control module 50 to ensure stability throughout the entire testing process. The power supply module 10 is used to power the multi-wavelength pulse laser 20. The multi-wavelength pulse laser 20 outputs laser pulses to the laser testing platform 40 for testing various laser performance parameters. The main control module 50 is used to collect external test parameters and internal telemetry of the multi-wavelength pulse laser 20. When the collected data exceeds the allowable range, the current status is recorded and reported to the alarm module 60. The alarm module 60 can control the power supply module 10 according to the abnormal state of the laser to achieve control of the working state of the multi-wavelength pulse laser 20 and ensure the safety of the test system. When the multi-wavelength pulse laser 20 is working normally, the main control module 50 can store, process and display and update the collected internal telemetry and external test data of the multi-pulse laser 20 in real time through the data processing module 70.

[0029] like Figure 2As shown, a schematic diagram of a test platform for multi-wavelength lasers, wherein the multi-wavelength is exemplified by three wavelengths, namely 1064nm, 532nm and 1572nm, wherein the three-wavelength pulse laser J1 is the test object (J11 is the reference mirror of the three-wavelength pulse laser J1), and the optical components and measuring equipment involved in the test are fixed on the test platform to ensure the stability of the test system. The test content includes directivity test, divergence angle and coincidence test, energy and polarization test, and pulse width and center wavelength test. The test implementation method is as follows: the directivity test is composed of a three-wavelength partial reflector M1, a reflector M12, a collimator B1 and an image sensor C1; the divergence angle and coincidence test is composed of a three-wavelength partial reflector M2, an off-axis telescope B2 and an image sensor C2; the energy and polarization test is composed of three-wavelength reflective mirrors M3, M6, M8, and a single wavelength partial reflector Mirrors M4, M7, M9, beam expanders M5-1, M5-2, M5-3, polarization test device B3, energy meters A1, A2, A3, A4; pulse width and center wavelength test consists of filters M10-1, M10-2, M10-3, coupling mirrors M11-1, M11-2, M11-3, fiber beam splitters D1, D2, D3, wavelength meters A5-1, A5-2, A5-3, photodetectors A6-1, A6-2, A6-3.

[0030] After the three-wavelength pulse laser J1 outputs a laser pulse that passes through the three-wavelength partial reflector M1, most of the energy is reflected by the three-wavelength partial reflector M2. A small portion of the energy is transmitted through M12 and then reflected to the collimator B1. After passing through the collimator B1, the light spot is collected by the image sensor C1, and the pointing deviation from the three-wavelength pulse laser J1's built-in reference mirror J11 is calculated to obtain the three-wavelength pulse directivity test result. The laser pulse incident on the three-wavelength partial reflector M2 is further split, and a small portion of the pulse energy is transmitted to the off-axis telescope B2. The light spot is collected by the image sensor C1, and the divergence angle of each wavelength laser and the overlap of the three wavelength lasers are calculated. The three-wavelength laser pulses reflected by three-wavelength partial reflector M2 are incident on three-wavelength transflector M3. The 1572nm pulse is reflected by 1572nm partial reflector M4, with most of its energy expanded by beam expander M5-1 before being incident on the 1572nm energy meter for collection. The other two wavelengths are transmitted through three-wavelength transflector M6. The 1064nm pulse is transmitted through three-wavelength transflector M8, and the 532nm pulse is reflected by polarization measurement device B3. The S light is collected by energy meter A2, and the P light passes through 532nm partial reflector M7. Most of its energy is expanded by beam expander M5-2 before being incident on 532nm energy meter A3 for collection. The polarization degree can be calculated by calculating the ratio of P light to S light. The 1064nm pulse passes through three-wavelength transflector M8 and 1572nm partial reflector M4. Most of its energy is expanded by beam expander M5-3 before being incident on the 1064nm energy meter for collection. The energy meter A1, A2, A3, and A4 coefficients and the actual transmittance of each optical element in the transmission light path for each wavelength have been calibrated. The actual energy of the three-wavelength pulse output by the laser can be calculated using the collected data of the three-wavelength energy meter and the calibration coefficient of the test equipment. The incident partial laser energy should be ensured to be less than 50% of the measuring range of the energy meters A1, A2, A3, and A4 to ensure the reliability of the test process data. A small portion of the 1572nm, 532nm and 1064nm laser pulses transmitted through the 1572nm partial reflector M4, the 532nm partial reflector M7 and the 1064nm partial reflector M9 respectively pass through the corresponding wavelength filters M10-1, M10-2, M10-3, coupling mirrors M11-1, M11-2, M11-3, and optical fiber splitters D1, D2, D3, and are incident on the corresponding wavelength wavelength meters A5-1, A5-2, A5-3 and photodetectors A6-1, A6-2, A6-3, and the pulse width and center wavelength of each wavelength are collected.

[0031] The three-wavelength partial reflectors M1 and M2 are plane mirrors made of BK7 or quartz material, and their surfaces are coated with a high-reflection film for 1572nm, 1064nm, and 532nm lasers incident at 45°, with a reflectivity of 99.5%. They are used to refract the light path of 1572nm, 1064nm, and 532nm lasers incident at 45°;

[0032] The reflector M12 is a plane mirror made of BK7 or quartz material, with a metal film or a dielectric film coated on its surface, and is used to collect the images of the three-wavelength laser and the reference mirror through the collimator to be collected by the image sensor C2.

[0033] The off-axis telescope B2 is composed of three reflecting mirrors, and the focal length of the off-axis telescope is ≥3m. It is used to focus the three-wavelength lasers on the photosensitive surface of the image sensor C2 and to calculate the divergence angle of each wavelength laser and the overlap between different wavelength lasers.

[0034] The three-wavelength transflective mirrors M3, M6, and M8 are plane mirrors made of BK7 or quartz materials, wherein the surface of the three-wavelength transflective mirror M3 is coated with a high-reflection film with a reflectivity of 99.8% for 1572nm incident at 45°, and an anti-reflection film with a reflectivity of 0.02% for 1064nm and 532nm incident at 45°; the surface of the three-wavelength transflective mirror M6 is coated with a high-reflection film with a reflectivity of 99.8% for 532nm incident at 45°, and an anti-reflection film with a reflectivity of 0.02% for 1064nm and 1572nm incident at 45°; the surface of the three-wavelength transflective mirror M8 is coated with a high-reflection film with a reflectivity of 99.8% for 1064nm incident at 45°, and an anti-reflection film with a reflectivity of 0.02% for 532nm and 1572nm incident at 45°. The three-wavelength transflective mirrors M3, M6, and M8 are used for three-wavelength light splitting.

[0035] The single wavelength partial reflectors M4, M7, and M9 are plane mirrors made of BK7 or quartz materials, and their surfaces are respectively coated with high-reflection films for 1572nm, 1064nm, and 532nm lasers incident at 45°, with a reflectivity of 99.5%. They are used to direct most of the laser energy into the energy meters A1, A2, A3, and A4, and to reflect a small portion of the laser light to test the pulse width and center wavelength.

[0036] The beam expanders M5-1, M5-2, and M5-3 are plano-concave mirrors made of BK7 or quartz material, and their surfaces are coated with an anti-reflection film for 0° incident 1572nm, 1064nm, and 532nm lasers, with a reflectivity of 0.02% and a concave curvature of 50mm. They are used to enlarge the laser spot to reduce the energy density incident on the energy meters A1, A2, A3, and A4.

[0037] The polarization degree testing device B3 is composed of a half-wave plate and three polarization splitting elements. The polarization splitting element is a polarization splitting prism or polarizer made of BK7 or quartz material. The half-wave plate adds a π phase to the 532nm laser to change the laser polarization state to P light. Polarization splitting is performed by the three polarization splitting elements and the energy of P light and S light in the laser is obtained respectively by the energy meters A3 and A4, thereby obtaining the measurement result of the laser polarization degree.

[0038] The filters M10-1, M10-2, and M10-3 are plane mirrors made of BK7 or quartz materials, and their surfaces are respectively coated with anti-reflection films for 0° incident 1572nm±2nm, 1064nm±2nm, and 532nm±2nm lasers, with transmittances greater than 70%. They are also respectively coated with high-reflection films for 0° incident lasers in bands other than the anti-reflection band, with reflectivities greater than 99.9%, to prevent scattered light from coupling to optical fibers and affecting the pulse width and center wavelength test results.

[0039] The coupling mirrors M11-1, M11-2, and M11-3 are plano-convex mirrors made of BK7 or quartz material, and their surfaces are respectively coated with anti-reflection films for 0° incident 1572nm, 1064nm, and 532nm lasers, with a reflectivity of 0.02% and a convex curvature of 50mm. The coupler is equipped with a fiber flange head, which is used to couple 1572nm, 1064nm, and 532nm lasers to the fiber cores of the fiber beam splitters D1, D2, and D3, respectively.

[0040] The fiber optic beam splitters D1, D2, and D3 are used to split the energy of the 1572nm, 1064nm, and 532nm lasers coupled to the optical fiber, respectively, with a splitting ratio of 1:1, and transmit them to the wavelength meters A5-1, A5-2, and A5-3 and photodetectors A6-1, A6-2, and A6-3 of the corresponding wavelengths to collect the pulse width and center wavelength results of each wavelength.

[0041] The optical components (including the three-wavelength partial reflectors M1 and M2, the three-wavelength transflective mirrors M3, M6, and M8, the single-wavelength partial reflectors M4, M7, and M9, the beam expanders M5-1, M5-2, and M5-3, the filters M10-1, M10-2, and M10-3, the coupling mirrors M11-1, M11-2, and M11-3, the reflector M12, and the polarization test device B3) are all subjected to surface testing and screening to ensure that the surface grading of the optical elements is better than 40 / 20, thereby reducing the influence of the surface shape of the optical elements on the test results.

[0042] The wavelength meters A5-1, A5-2, A5-3 and the photoelectric detectors A6-1, A6-2, A6-3 are all calibrated to reduce the error of the test results.

[0043] The laser test platform 40 is entirely covered and protected by a light shield made of black light-absorbing material to prevent scattered light during the laser test process from damaging the surrounding environment and human body.

[0044] Experiments have shown that the present invention can conduct comprehensive testing, data processing, and instant feedback on performance parameters such as laser energy, polarization degree, pulse width, central wavelength, divergence angle, overlap, and directivity, thereby improving the reliability of the test platform, reducing test errors, and fully verifying the working life of the laser.

[0045] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A test system for multi-wavelength pulsed lasers, characterized in that: include: a power supply module (10), electrically connected to the multi-wavelength pulse laser (20), and configured to supply power to the multi-wavelength pulse laser (20); A temperature control module (30) is electrically connected to the power supply module (10) and the multi-wavelength pulse laser (20), respectively, and is used to control the temperature of the power supply module (10) and the multi-wavelength pulse laser (20), and transmit temperature control data to the main control module (50), thereby ensuring a stable state throughout the entire test process; A laser testing platform (40) is used to receive the output laser pulses of the multi-wavelength pulse laser (20) to perform performance parameter testing and transmit the test results to a main control module (50); A main control module (50) is used to collect and process internal telemetry parameters and external test parameters of the multi-wavelength pulse laser (20), wherein the external test includes a directivity test, a divergence angle and coincidence test, an energy and polarization degree test, and a pulse width and center wavelength test; The laser test platform (40) comprises a first reflector (M1), a twelfth reflector (M12), a collimator (B1) and a first image sensor (C1) sequentially placed along an optical path for directivity testing; a second reflector (M2), an off-axis telescope (B2) and a second image sensor (C2) for divergence angle and coincidence testing; a plurality of multi-wavelength reflectors, a single-wavelength reflector, a beam expander, an energy meter and a polarization testing device (B3) for energy and polarization testing; and a plurality of optical filters, coupling mirrors, optical fiber beam splitters, wavelength meters and photodetectors for pulse width and center wavelength testing.

2. The test system for multi-wavelength pulse lasers according to claim 1, characterized in that: The main control module (50) is equipped with a control unit and a data transmission unit. The control unit is used to transmit laser control commands to the power supply module (10) to achieve control of the working state of the multi-wavelength pulse laser (20); and the data transmission unit is used to collect and transmit internal telemetry and external test data of the multi-wavelength pulse laser (20) to achieve real-time monitoring of the internal state of the multi-wavelength pulse laser (20).

3. The test system for multi-wavelength pulse lasers according to claim 1, characterized in that: The main control module (50) further includes an alarm module (60) which records the current state when the collected data exceeds an allowable range. The alarm module (60) then issues an alarm and controls the power supply module (10) according to the abnormal state of the multi-wavelength pulse laser (20) to control the working state of the multi-wavelength pulse laser (20) and ensure the safety of the test system.

4. The test system for multi-wavelength pulse lasers according to claim 1, characterized in that: The main control module (50) further comprises a data processing module (70), which is used for storing, processing and real-time displaying the collected internal telemetry and external test data of the multi-wavelength pulse laser.

5. The test system for multi-wavelength pulse lasers according to claim 1, characterized in that: The temperature control module (30) comprises a water-cooling circulation board and a water chiller. The water-cooling circulation board is used to control the temperature and dissipate heat of the power supply module (10) and the multi-wavelength pulse laser (20), and transmit temperature control data to the main control module (50) to ensure a stable state throughout the entire test process.

6. The test system for multi-wavelength pulse lasers according to claim 1, characterized in that: The central wavelength is obtained by splitting the laser output by the multi-wavelength pulse laser (20) by wavelength through a test optical path, coupling part of the energy to an optical fiber beam splitter via the coupling mirror, transmitting the energy to the wavelength meter to collect data, and transmitting the data to a main control module (50) for data processing and storage.

7. The test system for multi-wavelength pulse lasers according to claim 1, characterized in that: The laser directivity is determined by injecting a portion of the laser energy output by the multi-wavelength pulse laser (20) into the collimator through a test optical path, collecting the light spot via the image sensor and transmitting it to the main control module (50), and respectively reading the centroid coordinates ([Xλn, Yλn]) of each wavelength laser pulse and the centroid coordinates ([x, y]) of the multi-wavelength pulse laser's own reference mirror. The directivity test results are: The image sensor needs to be placed at the focal plane of the collimator, and F is the focal length of the collimator.

8. The test system for multi-wavelength pulse lasers according to claim 1, characterized in that: The polarization degree test is to split the laser output by the multi-wavelength pulse laser (20) according to wavelength through a test optical path and inject part of the energy into a polarization degree test device (B3), wherein the polarization degree test device is composed of a half-wave plate and a plurality of polarization splitting elements, wherein the plurality of polarization splitting elements are used to improve the polarization degree test accuracy, and the energy of the P light and the S light obtained by the polarization degree test device is respectively collected by the energy meter and transmitted to the main control module (50), and the polarization contrast of the multi-wavelength pulse laser is calculated. Wherein, EP and ES are the P light and S light energies.

Images