Device, system and method for adjusting optical power and detecting bandwidth of photoelectric detection module

Abstract

The invention relates to the technical field of dynamic light control and photoelectric conversion equipment, in particular to a device, a system and a method for adjusting light power and detecting bandwidth of a photoelectric detection module. A first polaroid and a second polaroid are arranged in the light emitting direction; the first polaroid and the second polaroid are both perpendicular to the optical axis, the first polaroid is located between the light source and the second polaroid, the second polaroid rotates in the direction perpendicular to the optical axis, and the optical power is adjusted by rotating the angle of the second polaroid. Circuit control of optical power adjustment is converted into mechanical rotation control of the second polaroid, and compared with a traditional mode of adjusting optical power through voltage or current, the bandwidth requirement of a power driving circuit is lowered. Under the condition that the output power of the light source is stable, the frequency of the output light source is adjusted by controlling the rotating speed of the polaroid, so that the parameter test of the photoelectric detection module in a wide dynamic range is realized. Through cooperation of the two polaroids and rotation of the second polaroid, a flexible, accurate and low-cost optical power adjusting mode is achieved, and nonlinear distortion and waveform distortion caused by direct modulation of a traditional light source are avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of dynamic light control and photoelectric conversion equipment, and in particular to a device, system and method for adjusting optical power and detecting bandwidth of a photoelectric detection module. Background Art

[0002] The photoelectric detection module is the core component of photoelectric conversion. The bandwidth of the photoelectric detection module determines its ability to respond to changes in optical input power.

[0003] Evaluating the bandwidth of photoelectric detection modules is a crucial step in ensuring stable and accurate performance of photoelectric detection systems. In applications such as spectral analysis and laser ranging, the bandwidth of photoelectric detection modules directly impacts the accuracy and precision of signal detection. In particular, when evaluating parameters such as the signal-to-noise ratio (SNR) of image intensifiers, accurately measuring the bandwidth of the photoelectric conversion module is crucial for obtaining accurate SNR test results.

[0004] Currently, the bandwidth of photodetection modules is often measured by directly controlling the light source output. For example, by varying the drive current of a halogen lamp or LED, the light energy output is adjusted to produce a sinusoidal-like variation in light energy. However, this approach places high demands on the driver circuit, resulting in high implementation costs. Furthermore, due to the limited signal bandwidth of the driver circuit, the output frequency of the drive current is limited. Furthermore, dynamic range adjustment is typically achieved by adjusting the drive current, but the achievable dynamic range is limited.

[0005] In summary, the current method of controlling the light source power to test the bandwidth of the photoelectric detection module has high driving circuit costs, limited light source power fluctuation range, and difficult to guarantee control accuracy. Summary of the Invention

[0006] In order to overcome the defect of the above-mentioned prior art in the lack of a high-precision bandwidth evaluation method for the photoelectric detection module, the present invention proposes an optical power adjustment method that can achieve large-scale and high-precision dynamic control of optical power, laying a high-precision foundation for the bandwidth detection of the photoelectric detection module.

[0007] The present invention proposes a method for adjusting optical power, in which a first polarizer and a second polarizer are arranged in the light emitting direction; the first polarizer and the second polarizer are both perpendicular to the optical axis, the first polarizer is located between the light source and the second polarizer, and the second polarizer rotates in a direction perpendicular to the optical axis. The light emitting power of the second polarizer is P o =P p ·cos 2 (θ+a); P p is the peak power output of the light source; θ is the angle of rotation of the second polarizer relative to the initial position, a is the polarization angle difference between the second polarizer in the initial position and the first polarizer; P ois the light output power of the second polarizer.

[0008] Preferably, the polarization angle of the second polarizer in the initial position is consistent with the polarization angle of the first polarizer.

[0009] The present invention proposes an optical power adjustment device, comprising a frame, a first polarizer, and a second polarizer; the frame is used to provide an optical channel, and the first polarizer and the second polarizer are arranged on the frame and located in the optical channel; the frame is also provided with an inlet and an outlet, and light from the light source enters the optical channel through the inlet, and then passes through the first polarizer and the second polarizer in sequence before being emitted from the outlet; the first polarizer and the second polarizer are both perpendicular to the optical axis, and the second polarizer rotates on its own plane.

[0010] Preferably, a driving device is further included, and the driving device is used to drive the second polarizer to rotate at a constant speed.

[0011] Preferably, the frame adopts a circular tube structure, and a positioning groove protruding outward is provided on the tube wall. A ring structure is provided in the positioning groove. The cross-section of the ring structure is H-shaped, and its inner periphery is used to fix the second polarizer. The outer periphery of the intermediate member is provided with a tooth portion; the top of the ring structure extends out of the tube wall, and the ring structure is engaged with a transmission disk arranged on the outside of the tube wall. The driving device drives the transmission disk to drive the ring structure to rotate.

[0012] The present invention proposes a photoelectric detection module bandwidth detection system, comprising: an optical power adjustment device, a light source, an electrical signal detection module and a control processor module;

[0013] The light output by the light source is output through the optical power adjustment device, the photoelectric detection module to be tested converts the light output by the optical power adjustment device into an electrical signal and outputs it, and the electrical signal detection module is used to detect the electrical signal output by the photoelectric detection module;

[0014] The control processing module is used to control the rotation of the second polarizer to adjust the frequency of the optical signal received by the photoelectric detection module; the control processing module is also used to receive and analyze the electrical signal output by the photoelectric detection module to obtain the bandwidth of the photoelectric detection module.

[0015] Preferably, the light source is an integrating sphere.

[0016] The present invention proposes a method for detecting the bandwidth of a photoelectric detection module. First, the optical power adjustment method is used to generate light output related to the rotation angle of the second polarizer as dynamic light when the optical power of the light source is stable. The light source is activated, the dynamic light is received by the photoelectric detection module and photoelectrically converted, and the electrical signal output of the photoelectric detection module is monitored.

[0017] The rotation speed of the second polarizer is adjusted from slow to fast, and at each rotation speed, at least one cycle of the electrical signal wave output by the photoelectric detection module is collected to extract the peak amplitude value;

[0018] The amplitude attenuation process of the electrical signal wave is tracked, and the rotation frequency of the second polarizer at the specified peak attenuation amplitude is extracted as the bandwidth of the photoelectric detection module.

[0019] Preferred:

[0020] S1. Set the initial rotation frequency f0 of the second polarizer to 0.5 Hz ≤ f0 ≤ 10 Hz;

[0021] S2, collecting at least one cycle of the electrical signal output by the photoelectric detection module and extracting the amplitude peak value V0;

[0022] S3, increasing the rotation frequency of the second polarizer to f1, f1>f0; collecting at least one cycle of the electrical signal output by the photoelectric detection module, and extracting the amplitude peak value V1;

[0023] S4, determine whether V1 is less than V0; if yes, reduce f0 and then return to step S2; if no, take amplitude V0 as the peak amplitude and execute step S5;

[0024] S5, adjust the rotation frequency of the second polarizer until the peak value V of the electrical signal output by the photoelectric detection module reaches the amplitude V0. The current rotation frequency of the second polarizer is extracted and recorded as the 3dB bandwidth of the photoelectric detection module.

[0025] Preferably, during the detection process, the range of the second polarizer rotation angle θ when the photoelectric detection module outputs an electrical signal is obtained, and the formula P is used. o =P p ·cos 2 (θ) Calculate the optical power of dynamic light;

[0026] An optical power detection module is used to detect the output electrical power of the photoelectric detection module, and a mapping relationship between the output electrical power of the photoelectric detection module and the optical power received by the photoelectric detection module is constructed by combining the rotation angle θ of the second polarizer with the time synchronization of the electrical power.

[0027] (1) The present invention proposes a method for adjusting optical power, which uses two polarizers and adjusts the optical power by rotating the angle of the second polarizer. The present invention converts the circuit control of optical power adjustment into mechanical rotation control of the second polarizer. Compared with the traditional method of adjusting optical power by voltage or current, the polarization angle control has higher mechanical precision and repeatability, and the mechanical structure is more stable. In addition, the rotation of the polarizer can achieve continuous adjustment without step changes, so the dynamic range may be wider. The present invention realizes a flexible, accurate and low-cost optical power adjustment method through the cooperation of the two polarizers and the rotation of the second polarizer, avoiding the nonlinear distortion and waveform distortion of the traditional direct modulation of the light source.

[0028] (2) In the present invention, the angle of the second polarizer in the initial position is consistent with that of the first polarizer, which is more conducive to tracking the rotation angle of the second polarizer to accurately calculate the adjusted optical power.

[0029] (3) The optical power adjustment device proposed in the present invention, through the arrangement of the frame, the annular structure and the transmission disk, makes the rotation of the second polarizer smoother and reduces jitter, thereby improving the adjustment accuracy. The uniform rotation of the drive device may bring about frequency stability, thereby improving the accuracy of the detection system. The design of the H-shaped annular structure and the tooth portion enhances the durability and precise engagement of the components, is not easy to wear out after long-term use, is conducive to maintaining accuracy and extending service life. In the present invention, the rotational motion is limited to a plane through the transmission disk engagement mechanism, effectively suppressing the tilt of the polarizer and ensuring the consistency of the optical axis, thereby improving the optical power adjustment accuracy.

[0030] (4) The photoelectric detection module bandwidth detection system proposed in the present invention uses an optical power adjustment device in conjunction with a light source and an electrical signal detection module for bandwidth detection of the photoelectric detection module; this ensures the stability of the dynamic optical signal during the detection process, thereby ensuring detection accuracy. The control processing module adjusts the rotation speed of the polarizer to change the frequency of the optical signal, which can flexibly generate dynamic optical signals of different frequencies, making it easier to test the response of the photoelectric detection module at different frequencies, thereby accurately measuring the bandwidth. In addition, the present invention can generate a continuously adjustable light intensity modulation signal through the rotation speed control of the optical power adjustment device, which meets the full-band test requirements of the photoelectric detection module. In addition, the integrating sphere as a light source provides uniform light output to reduce errors.

[0031] (5) The bandwidth detection method of the photoelectric detection module proposed in the present invention can accurately find the specified bandwidth, such as 3dB bandwidth, by adjusting the rotation speed of the polarizer, gradually increasing the frequency and monitoring the attenuation of the electrical signal amplitude.

[0032] (6) In the present invention, by comparing the amplitudes of the electrical signals at different rotational frequencies, the maximum amplitude can be automatically found through logical judgment, providing accuracy assurance for the electrical signal attenuation judgment. The application of the present invention is conducive to the automation of the bandwidth detection process of the photoelectric detection module, reducing human errors and improving efficiency.

[0033] (7) The present invention can also synchronously record the rotation angle and electrical power to establish a mapping relationship, thereby improving the accuracy of detection and eliminating other interference factors. The present invention provides high-precision and flexible photoelectric detection module bandwidth detection through polarizer rotation control, stable mechanical structure, and high system integration, which can effectively evaluate the performance of the photoelectric detection module.

[0034] (8) This invention, through its innovative polarization modulation mechanism and precision mechanical design, has achieved the first fully mechanical dynamic light field construction in the field of photoelectric detection. Compared with traditional electronic modulation methods, it has significant advantages in dynamic range, linearity and long-term stability, and is particularly suitable for the precise characterization of high-speed photoelectric detection modules. This invention is used for bandwidth measurement of photoelectric detection modules and has important practical significance and application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a flow chart of the optical power adjustment method proposed in the present invention;

[0036] Figure 2 This is a schematic diagram of the optical power adjustment device proposed in the present invention;

[0037] Figure 3 This is a cross-sectional view of the optical power adjustment device proposed by the present invention;

[0038] Figure 4 This is a cross-sectional view of the optical power adjustment device proposed by the present invention;

[0039] Figure 5 This is a flow chart of the bandwidth detection method of the photoelectric detection module proposed in the present invention;

[0040] Figure 6 is a correlation diagram between the transmittance of the real light adjustment device and the rotation angle of the second polarizer in the embodiment;

[0041] Figure 7 This is a graph showing the correlation between electrical signals, optical signals, and polarizer angle at 1 Hz;

[0042] Figure 8 This is a comparison chart of electrical signal and optical signal at 1Hz;

[0043] Figure 9 This is a comparison chart of electrical signals and optical signals at 100Hz;

[0044] Figure 10 This is the module diagram of the bandwidth detection system of the photoelectric detection module.

[0045] Diagram: 11-tube; 12-incident plate; 13-exit plate; 14-positioning slot; 2-first polarizer; 3-second polarizer; 4-transmission plate; 5-motor; 6-ring structure DETAILED DESCRIPTION

[0046] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0047] Reference Figure 1 In the optical power adjustment method proposed in this embodiment, a first polarizer 2 and a second polarizer 3 are arranged in the light output direction; the first polarizer 2 and the second polarizer 3 are both perpendicular to the optical axis, the first polarizer 2 is located between the light source and the second polarizer 3, and the second polarizer 3 rotates in a direction perpendicular to the optical axis, that is, on the plane where the second polarizer 3 is located; the light output power of the second polarizer 3 is: P o =P p ·cos 2 (θ+a);

[0048] Among them, P p is the peak power output of the light source; θ is the rotation angle of the second polarizer 3 relative to the initial position. When the second polarizer 3 is driven by the motor 5, θ is the rotation angle of the motor 5 relative to the zero point; a is the polarization angle difference between the second polarizer 3 in the initial position and the first polarizer 2; P o is the light output power of the second polarizer 3.

[0049] In specific implementation, the polarization angle of the second polarizer 3 in the initial position can be set to be consistent with the polarization angle of the first polarizer 2, that is, a=0. In this way, when the second polarizer 3 is in the initial position, the light output power P of the second polarizer 3 is o The largest one is helpful to simplify the operation.

[0050] This embodiment flexibly utilizes the principle of polarization, combining two polarizers with high-precision control of the output light power to convert optical power control into control of the rotation angle of the second polarizer 3. Compared to controlling optical power through the light source driver circuit, controlling the polarizer angle in this embodiment is more flexible. Furthermore, by controlling the uniform rotation speed of the second polarizer 3, uniform variations in the output light power can be achieved, thereby achieving uniform, stable, and flexibly controllable dynamic light.

[0051] The light source can be an integrating sphere. The peak output power of the integrating sphere can be set as needed, determined by the number of halogen lamps, the output power, and the aperture size. The light output power of the integrating sphere is more stable than that of light sources such as xenon lamps and lasers, which helps further ensure the controllability of the light output from the second polarizer 3.

[0052] Reference Figure 2 、 Figure 3 、 Figure 4The present embodiment proposes an optical power adjustment device, comprising a frame, a first polarizer 2 and a second polarizer 3; the frame is used to provide a circular tube-shaped optical channel, and the first polarizer 2 and the second polarizer 3 are arranged on the frame and located in the optical channel.

[0053] The frame is also provided with an incident port and an exit port. Light from the light source enters the light channel through the incident port, and then passes through the first polarizer 2 and the second polarizer 3 in sequence before being emitted from the exit port.

[0054] Specifically, the frame includes a tube body 1111, a first end plate 12, and a second end plate 13. The first and second end plates 12, 13 seal the ends of the tube body 1111 and are perpendicular to the centerline of the tube body 1111. An inlet 120 and an outlet 130 are provided on the first and second end plates 12, 13, respectively. The inlet 120 and outlet 130 can be located at the center of the respective end plates to facilitate the integration of external equipment with the optical power adjustment device and facilitate optical path construction.

[0055] The first polarizer 2 and the second polarizer 3 are both perpendicular to the optical axis, and the second polarizer 3 rotates in its own plane. The first polarizer 2 is used to convert incident light into linearly polarized light; the second polarizer 3 is adjusted by rotating the angle to control the transmittance of the linearly polarized light, thereby achieving flexible control of the optical power of the light emitted by the second polarizer 3, converting optical power adjustment into rotation angle adjustment of the second polarizer 3.

[0056] As the second polarizer 3 rotates, the difference between the polarization angle of the second polarizer 3 and the polarization angle of the first polarizer 2 changes periodically, so that the light output power of the second polarizer 3 and the rotation angle of the second polarizer 3 show periodic changes, that is: P o =P p ·cos 2 (θ+a).

[0057] In this way, the light output power at the exit can be controlled by precisely controlling the rotation angle of the second polarizer 3. In specific implementation, the second polarizer 3 can be driven to rotate at a constant speed by a driving device, thereby achieving uniform variation of the light output power at the exit.

[0058] Light source is used to provide light. o At the same time and P p ,θ correlation, P p The stability of P o The mapping with θ is stable. In this embodiment, the light source can specifically be an integrating sphere. Compared with xenon lamps, lasers, etc., the light wavelength and optical power of the integrating sphere are more stable, which is conducive to ensuring the accuracy of the light output power calculated in combination with the rotation angle of the second polarizer 3, and reducing the bandwidth evaluation error caused by the instability of the light source.

[0059] The first polarizer 2 and the second polarizer 3 are arranged inside the tube 1111 .

[0060] The tube body 1111 is provided with an outwardly protruding, open, annular positioning groove 14. An annular structure 6 is positioned within this groove. The annular structure 6 has an H-shaped cross-section, and its inner circumference is used to secure the second polarizer 3, thereby driving the rotation of the second polarizer 3. The center portion of the annular structure 6 is provided with teeth. The top of the annular structure 6 extends beyond the tube body 1111. A transmission disk 4 is positioned on the outer circumference of the tube body 1111 and engages with the teeth of the annular structure 6. The transmission disk 4 is driven by a drive device, namely a motor 5. The transmission disk 4 rotates the annular structure 6 and the second polarizer 3, thereby controlling the power of the emitted light by adjusting the rotation angle of the second polarizer 3.

[0061] Positioning slots 14 provide a guide and constraint for the rotation of annular structure 6, ensuring spatial stability for the rotation of annular structure 6 and second polarizer 3. The transmission disk 4 drives the rotation of annular structure 6, resulting in a simple structure and easy control of the speed and switch of motor 5, thus realizing a low-cost, highly reliable optical power adjustment device.

[0062] Reference Figure 5 This embodiment also provides a method for detecting the bandwidth of a photoelectric detection module. First, a light source, an optical power adjustment device, a photoelectric detection module to be tested, and an optical signal detection module are set. The light output by the light source is output through the optical power adjustment device. The photoelectric detection module to be tested converts the light output by the optical power adjustment device into an electrical signal for output. The electrical signal detection module is used to detect the electrical signal output by the photoelectric detection module.

[0063] Then, the light source is started to drive the second polarizer 3 to rotate at a constant speed to adjust the light output power of the optical power adjustment device to form a periodic signal; and the amplitude of the optical signal output by the photoelectric detection module at each rotation frequency of the second polarizer 3 is tracked to analyze the bandwidth of the photoelectric detection module, specifically a 3dB bandwidth can be selected.

[0064] In a specific implementation, first, the second polarizer 3 is rotated slowly, for example, the rotation frequency is 1 Hz or 10 Hz, and the amplitude of the electric signal is obtained as the maximum amplitude; then the rotation speed of the second polarizer 3 is increased until the amplitude of the electric signal is attenuated, and then the amplitude of the electric signal attenuated to the maximum amplitude is obtained. When , the rotation frequency of the second polarizer 3 at this time is obtained as the 3dB bandwidth of the photoelectric detection module.

[0065] In specific implementation, the stable change of the optical signal is conducive to the stability of the waveform of the electrical signal. The optical power output by the optical adjustment device meets P o =P p ·cos 2 (θ+a), P o is the output power of the optical power regulating device, Pp is the peak power output by the light source, θ is the rotation angle of the second polarizer 3 relative to the initial position, and a is the polarization angle difference between the second polarizer 3 and the first polarizer 2 at the initial position.

[0066] In this embodiment, an integrating sphere is used as a light source, and the luminous body of the integrating sphere can be a luminous body with a wavelength of 350nm to 2500nm; if used to test an ultraviolet detector, the luminous body adopts an ultraviolet light source.

[0067] In specific implementation, a=0 can be set to simplify the formula P o =P p ·cos 2 (θ).

[0068] In specific implementation, the mapping relationship between the output electrical power of the photoelectric detection module and the received optical power of the photoelectric detection module can be correlated according to time synchronization to further analyze the characteristics of the photoelectric detection module. The received optical power of the photoelectric detection module is the optical power output by the optical power adjustment device.

[0069] This embodiment also provides a photoelectric detection module bandwidth detection system, including: an optical power adjustment device, a light source, an electrical signal detection module and a control processor module;

[0070] The light output by the light source is output through the optical power adjustment device, the photoelectric detection module to be tested converts the light output by the optical power adjustment device into an electrical signal and outputs it, and the electrical signal detection module is used to detect the electrical signal output by the photoelectric detection module;

[0071] The control processing module is used to control the rotation angle and speed of the second polarizer 3 and receive the electrical signal detection value; the control processing module counts the electrical signal amplitude at different rotation speeds of the second polarizer 3 to calculate the bandwidth of the photoelectric detection module, so as to implement the above-mentioned photoelectric detection module bandwidth detection method.

[0072] The following is a verification of the above-mentioned photoelectric detection module bandwidth detection system and method in conjunction with specific embodiments. Figure 10 .

[0073] In the following embodiments, an integrating sphere is used as a light source; in the bandwidth detection system of the photoelectric detection module, a=0; a motor 5 is used as a driving device to drive the second polarizer 3 in the optical power adjustment device to rotate at a constant speed; a spectrometer is used to detect the output light power of the optical power adjustment device, and the ratio of the output light power of the optical power adjustment device to the peak power of the integrating sphere is calculated as the transmittance.

[0074] In this embodiment, the transmittance is related to the cosine square of the angle between the second polarizer 3 and the second polarizer 3. 2 The correlation of (θ) is as follows Figure 6As shown, it can be seen that the two are basically consistent with each other, which proves the reliability of dynamically adjusting the optical signal according to the rotation speed of the second polarizer 3 in this embodiment.

[0075] In this embodiment, when the rotation speed of the second polarizer 3 is 1 Hz, the relationship between the measured output voltage of the photoelectric detection module and the rotation angle θ of the second polarizer 3 is as follows: Figure 7 、 Figure 8 As shown, the electrical signal amplitude is perfectly consistent with the optical signal amplitude, and the transmittance variation trend is periodically correlated with the rotation angle θ, consistent with theoretical derivation. The electrical signal amplitude at this point is at its maximum, which is 5V. Theoretical derivation shows that the rotation frequency of the second polarizer 3, when the electrical signal attenuates to 5V × 0.707 = 3.535V, is the 3dB bandwidth of the photodetection module.

[0076] In this embodiment, when the rotation speed of the second polarizer 3 is 100 Hz, the relationship between the measured output voltage of the photoelectric detection module and the rotation angle θ of the second polarizer 3 is as follows: Figure 9 As shown, at this time, the amplitude of the electrical signal is close to 3.5V, so 100Hz is used as the 3dB bandwidth of the photoelectric detection module to be tested.

[0077] In this embodiment, the IV amplifier circuit gain resistor is 0.475GΩ, the compensation capacitor is 3.3pF, and the equivalent bandwidth of the photodetection module calculated based on the circuit parameters is 101.6Hz. Thus, the 3dB bandwidth obtained using the method of the present invention is 100Hz, and the calculated equivalent bandwidth is 101.6Hz, with a deviation of less than 2%, demonstrating the accuracy of the present invention.

[0078] Of course, it will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, but also encompasses the same or similar structures that can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and it is intended that all variations that fall within the meaning and range of equivalents of the claims be encompassed within the present invention. Any reference signs in the claims should not be construed as limiting the claim to which they relate.

[0079] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0080] The technology, shape, and structure not described in detail in the present invention are all well-known technologies.

Claims

1. A method for adjusting optical power, characterized in that: A first polarizer (2) and a second polarizer (3) are arranged in the light emitting direction; the first polarizer (2) and the second polarizer (3) are both perpendicular to the optical axis, the first polarizer (2) is located between the light source and the second polarizer (3), the second polarizer (3) rotates in a direction perpendicular to the optical axis, and the light emitting power of the second polarizer (3) is P o =P p ·cos 2 (θ+a); P p is the peak power output by the light source; θ is the angle at which the second polarizer (3) rotates relative to the initial position; a is the polarization angle difference between the second polarizer (3) at the initial position and the first polarizer (2); P o is the light output power of the second polarizer (3).

2. The optical power adjustment method according to claim 1, wherein: The polarization angle of the second polarizer (3) at the initial position is consistent with the polarization angle of the first polarizer (2).

3. An optical power adjustment device for implementing the optical power adjustment method according to claim 1 or 2, characterized in that: The invention comprises a frame, a first polarizer (2) and a second polarizer (3); the frame is used to provide a light channel, the first polarizer (2) and the second polarizer (3) are arranged on the frame and located in the light channel; the frame is also provided with an inlet and an outlet, light from a light source enters the light channel through the inlet, then passes through the first polarizer (2) and the second polarizer (3) in sequence and is emitted from the outlet; the first polarizer (2) and the second polarizer (3) are both perpendicular to the optical axis, and the second polarizer (3) rotates on its own plane.

4. The optical power adjustment device according to claim 3, wherein: It also includes a driving device, which is used to drive the second polarizer (3) to rotate at a uniform speed.

5. The optical power adjustment device according to claim 4, wherein: The frame adopts a circular tube structure, and a positioning groove (14) protruding outward is provided on the tube wall. An annular structure (6) is provided in the positioning groove (14). The annular structure (6) has an H-shaped cross section, and its inner periphery is used to fix the second polarizer (3). A tooth portion is provided on the outer periphery of the intermediate member. The top of the annular structure (6) protrudes from the tube wall, and the annular structure (6) is engaged with a transmission disk (4) arranged outside the tube wall. A driving device drives the transmission disk (4) to drive the annular structure (6) to rotate.

6. A photoelectric detection module bandwidth detection system using the optical power adjustment device according to claim 3, 4 or 5, characterized in that: include: Optical power adjustment device, light source, electrical signal detection module and control processor module; The light output by the light source is output through the optical power adjustment device, the photoelectric detection module to be tested converts the light output by the optical power adjustment device into an electrical signal and outputs it, and the electrical signal detection module is used to detect the electrical signal output by the photoelectric detection module; The control processing module is used to control the rotation of the second polarizer (3) to adjust the frequency of the optical signal received by the photoelectric detection module; the control processing module is also used to receive and analyze the electrical signal output by the photoelectric detection module to obtain the bandwidth of the photoelectric detection module.

7. The photoelectric detection module bandwidth detection system according to claim 6, characterized in that: The light source is an integrating sphere.

8. A method for detecting bandwidth of a photoelectric detection module using the optical power adjustment method according to claim 1 or 2, characterized in that: First, the optical power adjustment method as claimed in claim 1 or 2 is used to form the light output related to the rotation angle of the second polarizer (3) as dynamic light when the optical power of the light source is stable; the light source is started, the dynamic light is received by the photoelectric detection module and photoelectric conversion is performed, and the electrical signal output of the photoelectric detection module is monitored; The rotation speed of the second polarizer (3) is adjusted from slow to fast, and at each rotation speed, at least one cycle of the electrical signal wave output by the photoelectric detection module is collected to extract the amplitude peak value; The amplitude attenuation process of the electric signal wave is tracked, and the rotation frequency of the second polarizer (3) under the specified peak attenuation amplitude is extracted as the bandwidth of the photoelectric detection module.

9. The method for detecting bandwidth of a photoelectric detection module according to claim 8, wherein: S1, setting the initial rotation frequency f0 of the second polarizer (3), 0.5 Hz ≤ f0 ≤ 10 Hz; S2, collecting at least one cycle of the electrical signal output by the photoelectric detection module and extracting the amplitude peak value V0; S3, increasing the rotation frequency of the second polarizer (3) to f1, f1>f0; collecting at least one cycle of the electrical signal output by the photoelectric detection module, and extracting the amplitude peak value V1; S4, determine whether V1 is less than V0; if yes, reduce f0 and then return to step S2; if no, take amplitude V0 as the peak amplitude and execute step S5; S5, adjusting the rotation frequency of the second polarizer (3) until the peak value V of the electric signal output by the photoelectric detection module reaches the amplitude V0. The current rotation frequency of the second polarizer (3) is extracted and recorded as the 3dB bandwidth of the photoelectric detection module.

10. The method for detecting bandwidth of a photoelectric detection module according to claim 8, wherein: During the detection process, the range of the rotation angle θ of the second polarizer (3) when the photoelectric detection module outputs an electrical signal is obtained, and the formula P is used. o =P p ·cos 2 (θ) Calculate the optical power of dynamic light; An optical power detection module is used to detect the output electric power of the photoelectric detection module, and a mapping relationship between the output electric power of the photoelectric detection module and the received optical power of the photoelectric detection module is constructed by combining the rotation angle θ of the second polarizer (3) and the time synchronization of the electric power.

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