Photoelectric detector photoelectric response measuring method

Abstract

The invention discloses a photoelectric response measuring method for a photoelectric detector, belongs to the technical field of photoelectrons, and aims to provide a broadband and low-cost method for measuring the frequency response of the photoelectric detector. In the invention, an optical signal output by a laser is modulated by output signals of a first signal source and a second signal source in an electro-optical intensity modulator; the control and data processing module is used for controlling the frequency of an output signal of the first signal source to be fixed, changing the frequency of an output signal of the second signal source, inputting a modulated optical signal into the photoelectric detector to be detected, and the signal analysis module is used for analyzing a frequency component output by the photoelectric detector to be detected and extracting and eliminating the frequency response of the electro-optical intensity modulator. Finally, the photoelectric response of the to-be-measured photoelectric detector is measured.

Description

Technical Field

[0001] The invention belongs to a photoelectric response measurement technology of a photoelectric detector in the field of optoelectronic technology, and in particular relates to a photoelectric response measurement method of a photoelectric detector. Background Art

[0002] As the most commonly used light-to-electricity conversion device, photodetectors are widely used in optical communication links, data centers, microwave photon signal processing, etc. The measurement of photoelectric frequency response is very important for the characterization of broadband photodetector performance. Accurately measuring the photoelectric response of photodetectors will also help evaluate and optimize the ability of optoelectronic systems to transmit and process signals.

[0003] At present, there are two main methods for measuring the photoelectric response of photodetectors, namely the all-optical excitation method and the electro-optical excitation method. The all-optical excitation method mainly includes the optical wavelength beat method and the intensity noise method. The optical wavelength beat method uses two continuous wave lasers to beat each other through a photodetector, changing the wavelength of two or one of the lasers, which can achieve the measurement of the wide frequency range of the frequency response of the photodetector, but the frequency resolution of this method is limited by the wavelength adjustment accuracy of the laser, and the power stability of the laser is required to be high. The intensity noise method uses the wide spectrum signal output by the amplified spontaneous radiation light source to measure the frequency response of the photodetector. It has the characteristics of a wide frequency range, but the measurement accuracy of this method is very low and the dynamic range is poor. The electro-optical excitation method uses electro-optical modulation to generate high-coherence optical sidebands, with high frequency resolution and large dynamic range hotspots. The electro-optical excitation method mainly includes electro-optical sweep frequency method, dual-tone sweep frequency method and optical sampling method. The electro-optical frequency sweep method cascades a modulated laser or electro-optical intensity modulator with a known frequency response and the photodetector to be measured, and deducts the electro-optical response from the measured electro-electric response of the cascade network to obtain the photoelectric response of the photodetector to be measured. The electro-optical frequency sweep method requires electro-optical devices with known frequency response and the same bandwidth, which is not conducive to the measurement of broadband photodetectors. The dual-tone frequency sweep method uses two microwave frequency sweep sources with a fixed frequency interval to perform dual-tone modulation, and measures the sum and difference frequency signals output by the photodetector to obtain the frequency response of the photodetector. Summary of the invention

[0004] Aiming at the shortcomings of the existing photoelectric detector measurement method, the present invention provides a photoelectric response measurement method of a photoelectric detector, which has the characteristics of low cost, wide measurement frequency range and high resolution.

[0005] A method for measuring the photoelectric response of a photoelectric detector, characterized in that it includes the following steps and principles: Step 1: construct a photoelectric response measurement device for a photodetector, including a laser, an electro-optical intensity modulator, a photodetector to be measured, a signal analysis module, a first signal source, a second signal source, and a control and data processing module, wherein the laser, the electro-optical intensity modulator, and the photodetector to be measured are optically connected in sequence, the photodetector to be measured is electrically connected to the signal analysis module, the first signal source and the second signal source are electrically connected to the electro-optical intensity modulator, respectively, and the control and data processing module is data-connected to the first signal source, the second signal source, and the signal analysis module in sequence; Step 2: Determine the frequency f at which the photoresponse of the photodetector to be tested is measured M , set the first signal source signal frequency f LO and the second signal source signal frequency f IF , where frequency f M , frequency f LO and frequency f IF The relationship is satisfied: f M =kf LO ±f IF , k is only an even number or only an odd number; the frequency f LO The test remains unchanged, f LO It is generally equal to the 3dB bandwidth cutoff frequency of the electro-optical intensity modulator, and then calculate the frequency f M Divide by the frequency f LO The quotient of is recorded as N. When the parity of N is consistent with the parity of the configured k, k = N, and the signal frequency f of the second signal source can be calculated. IF =f M –kf LO When the parity of N is inconsistent with the parity of the configured k, take k = N + 1, and the second signal source signal frequency f can be calculated IF =kf LO –f M ; Step 3: The optical signal output by the laser is modulated by the first signal source and the second signal source respectively through the electro-optic intensity modulator. After the modulated optical signal is photoelectrically converted by the photodetector to be measured, the output photocurrent signal is collected and received by the signal analysis module; Step 4: The bias state of the electro-optic intensity modulator is set according to the parity of the configured k. When the configuration k is only an even number, the electro-optic intensity modulator is set to work at the linear transmission point; when the configuration k is only an odd number, the electro-optic intensity modulator is set to work at the maximum or minimum transmission point; Step 5: Set the receiving frequency of the signal analysis module according to the parity of the configured k, and measure the photocurrent signal amplitude at the corresponding frequency; set the receiving frequency of the signal analysis module to f M and (1+s)f LO , and measure the electrical signal amplitude at the corresponding frequency as i(f M;f IF ) and i[(1+s)f LO ;f IF ], where s = 0, 1, corresponding to the case where k is only an even number and only an odd number, respectively; Step 6: Change the signal frequency of the second signal source to f R , f R Satisfy f R ≈f LO Similarly, the receiving frequency of the signal analysis module is set according to the parity of the configured k; the receiving frequency of the signal analysis module is set to (2+s)f LO –f R 、s·f LO +f R 、(2+s)f R –f LO and (1+s)f LO , the electrical signal amplitude of the corresponding frequency is measured as i[(2+s)f LO –f R ;f R ]、i(s·f LO +f R ;f R )、i[(2+s)f R –f LO ;f R ] and i[(1+s)f LO ;f R ]; Step 7: Use the electrical signal amplitude i[(1+s)f measured in step 5 LO ;f IF ] and the electrical signal amplitude i[(2+s)f measured in step 6 LO –f R ;f R ]、i(s·f LO +f R ;f R )、i[(2+s)f R –f LO ;f R ] and i[(1+s)f LO ;f R ], calculate the modulation coefficient m of the electro-optical intensity modulator driven by the first signal source 1 (f LO ) and the modulation coefficient m driven by the second signal source 2 (f R ) and m 2 (f IF ), for the case where k is only an even number, s = 0, the calculation formula is: For the case where k is only an odd number, s = 1, and the calculation formula is: Among them, J n (m) is the nth-order Bessel function of the first kind; Step 8: Use the modulation coefficient m of the electro-optic intensity modulator calculated in step 7 1 (f LO ) and m 2 (f IF ), and the electrical signal amplitude i(f M ;f IF ), the frequency of the photoelectric detector to be measured can be calculated according to the following formula at frequency f M The photoelectric response is: Step 9: Change the test frequency f M , repeat step 2 to calculate the corresponding frequency f IF Repeat steps 3, 4 and 5 to measure the electrical signal amplitude i(f M ;f IF ) and i[(1+s)f LO ;f IF ], repeat step 7 to calculate the modulation coefficient m of the electro-optic intensity modulator 2 (f IF ), and then repeat step 8 to calculate the photoelectric detector to be tested at the frequency f M Photoelectric response R(f M ), from which different frequencies f can be calculated M The photoelectric response of the photodetector under test.

[0006] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention uses only one electro-optic intensity modulator for modulation, and has the characteristics of compact structure; 2. The present invention uses a fixed-frequency microwave signal source and a variable-frequency microwave signal source for modulation, which greatly reduces the cost of the test system while maintaining the characteristics of flexible and adjustable test frequency points of the photoelectric response of the photoelectric detector to be tested. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is a schematic diagram of the device of the present invention.

[0008] Figure 2 This is a test effect diagram when the parameter k described in the present invention is only an even number.

[0009] Figure 3This is a test effect diagram when the parameter k described in the present invention is only an odd number. DETAILED DESCRIPTION

[0010] The present invention is further described below in conjunction with embodiments, which are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, other embodiments obtained by ordinary technicians in the field without creative work are all within the protection scope of the present invention.

[0011] like Figure 1 As shown, the optical signal output by the laser is modulated by the first signal source and the second signal source respectively, and the modulated optical signal is detected by the photodetector and then outputs a photocurrent signal; the control and data processing modules respectively control the frequency of the first signal source to always be f LO , the second signal source frequencies are f IF and f R The signal analysis module is used to measure the different frequency components in the photocurrent output by the photodetector. The photoelectric response of the photodetector can be calculated based on the measured frequency component amplitude information. The control and data processing module is used to change the frequency f of the second signal source. IF , repeating the above steps can realize the test of photoelectric response of photodetector at different frequency points.

[0012] In order to better explain the technical invention solution, the principle and method of the present invention are briefly introduced below:

[0013] After the optical signal output by the Mach-Zehnder modulator is detected by the photodetector to be tested, the output photocurrent expression is: Where R is the responsivity of the photodetector to be measured, I 0 is the intensity of the optical carrier signal, γ is the splitting ratio of the Mach-Zehnder modulator, is the bias phase of the Mach-Zehnder modulator, m 1 (f LO ) is the output signal f of the first signal source LO The modulation coefficient of the Mach-Zehnder modulator under driving, m 2 (f IF ) is the output signal f of the second signal source IF Modulation coefficient of the driven Mach-Zehnder modulator.

[0014] According to formula (1), let k be a non-negative integer and q = 1. Then, the frequency component amplitude used to extract the frequency response of the photodetector to be measured can be obtained as:

[0015] According to formula (2), the frequency point at which the frequency response of the photodetector to be tested is measured is f M =kf LO ±f IF , set f LO is a fixed frequency, generally about the 3dB bandwidth cutoff frequency of the electro-optical intensity modulator in the test system, and then the parameters k and frequency f are changed. IF To adjust the frequency f of the photodetector frequency response M In order to simplify formula (2), the method configures the parity of k+1, that is, the parity of k, so that k is only an even number or only an odd number during the measurement process. In order to select appropriate parameters k and frequency f IF , thereby matching the frequency f M , here we calculate the frequency f M With frequency f LO The quotient is recorded as N. If the calculated quotient N is consistent with the parity of the configured k, take k = N, and then according to the formula f IF =f M –kf LO Calculate the required frequency f IF ; If the calculated quotient N is inconsistent with the parity of the configured k, take k = N + 1, and then according to formula f IF =kf LO –f M Calculate the required frequency f IF .

[0016] For the case where k is only even or only odd, the bias phase of the Mach-Zehnder modulator is set to or The frequency component amplitude in formula (2) can be simplified to: i(f M ;f IF )=4I 0 γJ k [m 1 (f LO )]J 1 [m 2 (f IF )]R(f M ). (3)

[0017] The control signal analysis module is used to analyze the frequency component (1+s)f LO The measured amplitude is recorded as i[(1+s)f LO ;f IF ], where s = 0, 1, corresponding to the case where k is only an even number and only an odd number, respectively. Set the output signal frequency of the second signal source to f R , the amplitudes are measured using the signal analysis module and recorded as i[(2+s)fLO –f R ;f R ]、i(s·f LO +f R ;f R )、i[(2+s)f R –f LO ;f R ] and i[(1+s)f LO ;f R ]. Because f R ≈f LO , satisfying R[(2+s)f LO –f R ]≈R(s·f LO +f R )≈R[(2+s)f R –f LO ]≈R[(1+s)f LO ], the modulation coefficient m of the Mach-Zehnder modulator can be obtained 1 (f LO )、m 2 (f R ) and m 2 (f IF ) is calculated as: Or:

[0018] The frequency response amplitude i(f M ;f IF ), based on formula (3) and formula (4) to formula (6) or formula (7) to formula (9), deduct the frequency response J of the electro-optic intensity modulator k [m 1 (f LO )] and J 1 [m 2 (f IF )], the photoelectric response of the photodetector to be tested can be obtained as:

[0019] Finally, based on formula (10), the output signal frequency f of the first signal source is fixed LO , adjust the frequency f M , calculate the corresponding frequency f M The frequency f IF , change the output signal frequency f of the second signal source IF , repeat the above operation, you can measure different frequencies f M The photoelectric response of the photodetector under test. Example 1

[0020] In this embodiment, the k parameter is only an even number. First, the test frequencies of the photoelectric response of the photodetector to be tested are determined to be 50 MHz (f M ) and 19.96GHz(f M ), the 3dB bandwidth of the electro-optic intensity modulator used is about 10GHz, so the output signal frequency of the first signal source is set to 10.005GHz (f LO ), divide 50MHz and 19.96GHz by 10.005GHz respectively, the quotients obtained are 0 and 1 respectively, so set the k value to 0 and 2 respectively, and calculate the second signal source frequency f IF 50MHz=50MHz–0×10.005GHz(f M –0×f LO ), 50MHz=2×10.005GHz–19.96GHz(2f LO –f M ), so the second signal source frequency f is set IF The optical signal with the output frequency of 193.1THz from the laser is sent to the electro-optic intensity modulator and is modulated by the first signal source with the frequency of 10.005GHz (f LO ) of the microwave signal and the second signal source with a frequency of 50MHz (f IF ) is modulated by microwave signals, and the modulated optical signal is sent to the photodetector to be tested for detection. The detected photocurrent is received by the signal analysis module. The electro-optic intensity modulator is set to work at the linear transmission point, and the frequencies are measured by the signal analysis module to obtain 50MHz (f M =f IF )、19.96GHz(f M =2f LO –f IF ) and 10.005GHz(f LO )’s frequency component amplitude information, recorded as i(f IF ;f IF )=-46.75dBm、i(2f LO –f IF ;f IF )=-43.91dBm and i(f LO ;f IF )=-47.83dBm. Set the second signal source frequency to 10.05GHz (f R ), the frequencies measured by the signal analysis module are 9.96GHz(2f LO –f R )、10.05GHz(f R)、10.095GHz(2f R –f LO ) and 10.005GHz(f LO )’s frequency component amplitude information, recorded as i(2f LO –f R ;f R )=-45.15dBm、i(f R ;f R )=-48.87dBm、i(2f R –f LO ;f R )=-64.06dBm and i(f LO ;f R )=-46.34dBm. Using the amplitude information i(2f LO –f R ;f R )=-45.15dBm and i(f R ;f R )=-48.87dBm, based on formula (4), the modulation coefficient m of the electro-optical intensity modulator modulated by the first signal source is calculated 1 (10.005GHz) is 3.18rad; using the amplitude information i(2f R –f LO ;f R )=-64.06dBm and i(f LO ;f R )=-46.34dBm, based on formula (5), the modulation coefficient m of the electro-optical intensity modulator modulated by the second signal source is calculated 2 (10.05GHz) is 0.94rad. Reusing the amplitude information i(f LO ;f IF )=-47.83dBm and i(f LO ;f R )=-46.34dBm, based on formula (6), the modulation coefficient m of the electro-optical intensity modulator modulated by the second signal source is calculated 2 (50MHz) is 1.21rad. The modulation coefficient m 1 (10.005GHz) = 3.18rad and m 2 (50MHz) = 1.21rad Substitute into formula (10) and use the amplitude information i(f IF ;f IF )=-46.75dBm and i(2f LO –f IF ;f IF )=-43.91dBm The photoelectric detector to be tested has a frequency of 50MHz (fM =f IF ) and 19.96GHz(f M =2f LO –f IF ) is -30.71dB and -31.61dB, and the relative frequency response of the photodetector to be tested at a frequency of 19.96GHz relative to 50MHz can be calculated to be -0.90dB. Repeat the above operation to obtain the photoelectric response of the photodetector to be tested in the measurement frequency range of 50MHz to 30.06GHz, as shown in Figure 2 shown. Example 2

[0021] In this embodiment, the k parameter is only an odd number. First, the test frequencies of the photoelectric response of the photodetector to be tested are determined to be 50 MHz (f M ) and 19.96GHz(f M ), the 3dB bandwidth of the electro-optic intensity modulator used is about 10GHz, so the frequency of the first signal source is set to 10.005GHz (f LO ), divide 50MHz and 19.96GHz by 10.005GHz respectively, the quotients obtained are 0 and 1 respectively, so set the k value to 1, and calculate the second signal source frequency f IF They are 9.955GHz=10.005GHz–50MHz(f LO –f M ), 9.955GHz=19.96GHz–10.005GHz(f M –f LO ), so the second signal source frequency f is set IF The optical signal with the output frequency of 193.1THz from the laser is sent to the electro-optic intensity modulator and is modulated by the first signal source with the frequency of 10.005GHz (f LO ) of microwave signal and the second signal source frequency is 9.955GHz (f IF ) is modulated by microwave signals, and the modulated optical signal is sent to the photodetector to be tested for detection. The detected photocurrent is received by the signal analysis module. The electro-optic intensity modulator is set to work at the maximum transmission point, and the frequencies measured by the signal analysis module are 50MHz (f M =f LO –f IF )、19.96GHz(f M =f LO +f IF ) and 20.01GHz(2f LO )’s frequency component amplitude information, recorded as i(f LO –f IF ;fIF )=-48.10dBm、i(f LO +f IF ;f IF )=-49.01dBm and i(2f LO ;f IF )=-38.85dBm. Set the second signal source frequency to 10.05GHz (f R ), and the frequencies measured by the signal analysis module are 19.965GHz(3f LO –f R )、20.145GHz(3f R –f LO )、20.055GHz(f LO +f R ) and 20.01GHz(2f LO )’s frequency component amplitude information, recorded as i(3f LO –f R ;f R )=-47.28dBm、i(3f R –f LO ;f R )=-77.48dBm、i(f LO +f R ;f R )=-49.3dBm and i(2f LO ;f R )=-38.71dBm. Using the amplitude information i(3f LO –f R ;f R )=-47.28dBm and i(f LO +f R ;f R )=-49.3dBm, based on formula (7), the modulation coefficient m of the electro-optical intensity modulator modulated by the first signal source is calculated 1 (10.005GHz) is 3.18rad; using the amplitude information i(3f R –f LO ;f R )=-77.48dBm and i(f LO +f R ;f R )=-49.3dBm, based on formula (8), the modulation coefficient m of the electro-optical intensity modulator modulated by the second signal source is calculated 2 (10.05GHz) is 0.94rad. Using the amplitude information i(2f LO ;f IF )=-38.85dBm and i(2f LO;f R )=-38.71dBm, based on formula (9), the modulation coefficient m of the electro-optical intensity modulator modulated by the second signal source is calculated 2 (9.955GHz) is 0.97rad. The modulation coefficient m 1 (10.005GHz) = 3.18rad and m 2 Substituting (9.955GHz)=0.97rad into formula (10), using the amplitude information i(f LO –f IF ;f IF )=-48.10dBm and i(f LO +f IF ;f IF )=-49.01dBm, and the photoelectric detector to be tested is calculated to have a frequency of 50MHz (f M =f LO –f IF ) and 19.96GHz(f M =f LO +f IF ) is -29.38dB and -30.29dB, and the relative frequency response of the photodetector to be tested at a frequency of 19.96GHz relative to 50MHz can be calculated to be -0.91dB. Repeat the above operation to obtain the photoelectric response of the photodetector to be tested in the measurement frequency range of 50MHz to 30.06GHz, as shown in Figure 3 shown.

Claims

1. A method for measuring the photoelectric response of a photodetector, characterized in that: The following steps are involved: Step 1: construct a photoelectric response measurement device for a photodetector, including a laser, an electro-optical intensity modulator, a photodetector to be measured, a signal analysis module, a first signal source, a second signal source, and a control and data processing module, wherein the laser, the electro-optical intensity modulator, and the photodetector to be measured are optically connected in sequence, the photodetector to be measured is electrically connected to the signal analysis module, the first signal source and the second signal source are electrically connected to the electro-optical intensity modulator, respectively, and the control and data processing module is data-connected to the first signal source, the second signal source, and the signal analysis module in sequence; Step 2: Determine the frequency f at which the photoresponse of the photodetector to be tested is measured M , set the first signal source signal frequency f LO and the second signal source signal frequency f IF , where frequency f M , frequency f LO and frequency f IF The relationship is satisfied: f M =kf LO ±f IF , k is only even or only odd; frequency f LO The test remains unchanged, f LO It is generally equal to the 3dB bandwidth cutoff frequency of the electro-optical intensity modulator, and then calculate the frequency f M Divide by the frequency f LO The quotient of is recorded as N. When the parity of N is consistent with the parity of the configured k, k = N, and the signal frequency f of the second signal source can be calculated. IF =f M –kf LO When the parity of N is inconsistent with the parity of the configured k, take k = N + 1, and the second signal source signal frequency f can be calculated IF =kf LO –f M ; Step 3: The optical signal output by the laser is modulated by the first signal source and the second signal source respectively through the electro-optical intensity modulator. After the modulated optical signal is photoelectrically converted by the photodetector to be measured, the output photocurrent signal is collected and received by the signal analysis module; Step 4: setting the bias state of the electro-optic intensity modulator according to the parity of the configured k. When the configured k is only an even number, the electro-optic intensity modulator is set to work at the linear transmission point; when the configured k is only an odd number, the electro-optic intensity modulator is set to work at the maximum or minimum transmission point; Step 5: Set the receiving frequency of the signal analysis module according to the parity of the configured k, and measure the photocurrent signal amplitude at the corresponding frequency; set the receiving frequency of the signal analysis module to f M and (1+s)f LO , and measure the electrical signal amplitude at the corresponding frequency as i(f M ;f IF ) and i[(1+s)f LO ;f IF ], where s = 0, 1, corresponding to the case where k is only even and only odd, respectively; Step 6: Change the frequency of the second signal source to f R , f R Satisfy f R ≈f LO Similarly, the receiving frequency of the signal analysis module is set according to the parity of the configured k; the receiving frequency of the signal analysis module is set to (2+s)f LO –f R 、s·f LO +f R 、(2+s)f R –f LO and (1+s)f LO , the electrical signal amplitude of the corresponding frequency is measured as i[(2+s)f LO –f R ;f R ]、i(s·f LO +f R ;f R )、i[(2+s)f R –f LO ;f R ] and i[(1+s)f LO ;f R ]; Step 7: Use the electrical signal amplitude i[(1+s)f measured in step 5 LO ;f IF ] and the electrical signal amplitude i[(2+s)f measured in step 6 LO –f R ;f R ]、i(s·f LO +f R ;f R )、i[(2+s)f R –f LO ;f R ] and i[(1+s)f LO ;f R ], calculate the modulation coefficient m1 (f LO ) and the modulation coefficient m2(f R ) and m2(f IF ), for the case where k is only an even number, s = 0, the calculation formula is: For the case where k is only an odd number, s = 1, and the calculation formula is: Among them, J n (m) is the first kind nth order Bessel function; Step 8: Use the modulation coefficient m1 (f LO ) and m2(f IF ), and the electrical signal amplitude i(f M ;f IF ), the frequency of the photoelectric detector to be measured can be calculated according to the following formula at frequency f M The photoelectric response is: Step 9: Change the test frequency f M Repeat step 2 to calculate the corresponding frequency f IF Repeat steps 3, 4 and 5 to measure the electrical signal amplitude i(f M ;f IF ) and i[(1+s)f LO ;f IF ], repeat step 7 to calculate the modulation coefficient m2 (f IF ), and then repeat step 8 to calculate the photoelectric detector to be tested at the frequency f M Photoelectric response R(f M ), from which different frequencies f can be calculated M The photoelectric response of the photodetector to be tested is further analyzed by changing the frequency f M Photoelectric response R(f M ) relative to the low frequency f M By normalizing, the relative frequency response of the photodetector to be tested can be obtained.

2. A method for measuring the photoelectric response of a photodetector according to claim 1, characterized in that: In step 2, the first signal source signal frequency f LO and the second signal source signal frequency f IF The setting method is: the signal frequency of the first signal source f LO It is generally equal to the 3dB bandwidth cutoff frequency of the electro-optical intensity modulator, and then calculate the frequency f M Divide by the frequency f LO The quotient of is recorded as N. When the parity of N is consistent with the parity of the configured k, k = N, and the signal frequency f of the second signal source can be calculated. IF =f M –kf LO When the parity of N is inconsistent with the parity of the configured k, take k = N + 1, and the second signal source signal frequency f can be calculated IF =kf LO –f M .

3. The method for measuring the photoelectric response of a photodetector according to claim 1, characterized in that: In step 2, the frequency f of the photoelectric response of the photodetector to be measured is measured. M With the first signal source signal frequency f LO and the second signal source signal frequency f IF The relationship is satisfied: f M =kf LO ±f IF , where k is either only even or only odd.

4. The method for measuring the photoelectric response of a photodetector according to claim 1, characterized in that: The modulation coefficient of the electro-optical intensity modulator is m1(f LO )、m2(f R ) and m2(f IF ) can be obtained by using different calculation formulas in step 7 according to the parity of the configured parameter k, When k is only an even number, the calculation formula used is: When k is only an odd number, the calculation formula used is: Among them, J n (m) is the nth-order Bessel function of the first kind.

5. The method for measuring the photoelectric response of a photodetector according to claim 1, characterized in that: The photoelectric response of the photodetector to be measured is obtained by subtracting the two different modulation responses of the electro-optic intensity modulator, and its calculation formula is:

Images