Resonant Balanced Zero-Beat Photodetector with Notch Characteristics, its Printing and Testing Devices

Abstract

This invention discloses a resonant balanced zero-beat photodetector with notch characteristics, its printing apparatus, and a testing apparatus, belonging to the field of photodetectors. By introducing an LC series resonant notch circuit into the resonant balanced zero-beat detector, and adjusting the fine-tuning capacitor in the LC series resonant notch circuit, noise at the repetition frequency of the pulsed light can be suppressed, ensuring optimal notch performance and improving the saturation power and signal-to-noise ratio of the photodetector under pulsed light. It can be applied to testing apparatuses for pulsed compressed light.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of photoelectric detectors, in particular to a resonant balanced homodyne photoelectric detector with a notch characteristic, and a printing device and a testing device thereof. BACKGROUND

[0002] In the field of quantum information science, squeezed state light field has the characteristics of breaking through the quantum noise limit in a certain component, and is a valuable quantum resource, which has wide application in spectral measurement, gravitational wave detection, quantum key distribution, etc. In recent years, laboratories have been measuring and experimenting on continuous variable light sources to apply continuous variable squeezed states to quantum teleportation, quantum radar, quantum precision measurement and sensing, etc. Due to high peak power and special pulse shape, pulse squeezing and entanglement have attracted more attention. At present, it has been proved that pulse squeezing can improve the signal-to-noise ratio of the detector to realize quantum microscopic imaging.

[0003] In the preparation of pulse squeezing and entanglement, in addition to high-quality compressors, high-performance photoelectric detection devices are also needed. Balanced homodyne detector is one of the key devices for realizing the detection of squeezed state and entangled state. Since the balanced homodyne detector was proposed, people have been working on developing a high signal-to-noise ratio and low noise detector. In 2009, the University of Pardubice and the Institute of Physics Optical Joint Laboratory developed a balanced homodyne detector with a bandwidth of 54 MHz, which obtained a signal-to-noise ratio of 12 dB under a pulse light power of 12 mW. In 2012, the research group of the University of Calgary in Canada developed a 100 MHz balanced homodyne detector, which obtained a signal-to-noise ratio of 13 dB under a pulse light power of 12 mW. In 2018, Professor Li Yongmin's research group of Shanxi University developed a balanced homodyne detector with a bandwidth of 40 MHz, which measured a signal-to-noise ratio of 14.50 dB under pulse light. The above photoelectric detectors all use the traditional transimpedance amplification structure, which has the characteristics of low noise, but cannot obtain high bandwidth and high voltage swing at the same time. The resonant detector can not be limited by the gain-bandwidth product, and can maintain high sensitivity and obtain high gain at the resonant frequency. In 2017, Professor Zheng Yaohui's research group of Shanxi University developed a single-probe resonant photoelectric detector with adjustable resonant frequency for squeezed state generation experiments. In 2018, the University of Tokyo developed a 500 MHz resonant balanced homodyne detector, which obtained a signal-to-noise ratio of 12 dB under a light power of 5 mW. In 2022, a 20 MHz resonant balanced homodyne detector was developed. Due to the limitation of the pulse light repetition frequency, only a signal-to-noise ratio of 10.02 dB was obtained under a light power of 3 mW. It can be seen that the saturation light power and signal-to-noise ratio of the detector under pulse light need to be improved. SUMMARY

[0004] The application aims to provide a resonant balanced homodyne photodetector with a notch characteristic, a printing device and a testing device, which can improve the saturation optical power and signal-to-noise ratio of the photodetector under pulsed light.

[0005] To achieve the above-mentioned purpose, the application provides the following solutions.

[0006] A resonant balanced homodyne photodetector with a notch characteristic comprises a photodetection module, an LC series resonant notch circuit, a first resonant type frequency selection amplification circuit, a second frequency selection network, an alternating current amplification module and a direct current amplification module; the photodetection module is used to convert an optical signal into an electrical signal and generate a photocurrent difference signal; the LC series resonant notch circuit comprises a first inductor and a trimming capacitor; one end of the trimming capacitor is connected to one end of the first inductor, and the other end of the trimming capacitor is grounded; the other end of the first inductor is connected between the photodetection module and the first resonant type frequency selection amplification circuit in the resonant balanced homodyne photodetector; the LC series resonant notch circuit is used to filter out a signal at a pulsed laser repetition frequency in the photocurrent difference signal detected by the photodetection module by adjusting the capacitance value of the trimming capacitor, and send the filtered photocurrent difference signal to the first resonant type frequency selection amplification circuit; the output end of the first resonant type frequency selection amplification circuit is connected to the input end of the second frequency selection network and the input end of the direct current amplification module, respectively; the first resonant type frequency selection amplification circuit is used to convert the filtered photocurrent difference signal into a first voltage signal at a resonant frequency and amplify the filtered photocurrent difference signal; the output end of the second frequency selection network is connected to the first input end of the alternating current amplification module; the second frequency selection network is used to perform second frequency selection on the first voltage signal at the resonant frequency to obtain a second voltage signal at the resonant frequency, and transmit the second voltage signal at the resonant frequency to the alternating current amplification module; the alternating current amplification module is used to amplify the second voltage signal at the resonant frequency to generate an alternating current voltage signal at the resonant frequency; and the direct current amplification module is used to filter out a direct current voltage signal from the first voltage signal at the resonant frequency and amplify the filtered direct current voltage signal.

[0007] A photodetector printing device, the printing device comprising a printed circuit board, an aluminum metal shell and the above-mentioned photodetector; the photodetector is printed on the printed circuit board; and the printed circuit board printed with the photodetector is sealed in the aluminum metal shell.

[0008] A photoelectric detector testing device, the testing device comprising: a laser source, a half-wave plate, a polarization beam splitter prism, a first mirror, a second mirror, a first lens, a second lens, a spectrum analyzer, an oscilloscope and the photoelectric detector. The AC voltage output end of the photoelectric detector is connected with the spectrum analyzer, and the DC voltage output end of the photoelectric detector is connected with the oscilloscope. The laser source is used for generating picosecond pulse light with a repetition frequency; the picosecond pulse light is transmitted to the polarization beam splitter prism after passing through the half-wave plate. The polarization beam splitter prism is used for splitting the picosecond pulse light into two beams, one of which is reflected to the first lens through the first mirror, and the other of which is reflected to the second lens through the second mirror. The first lens is used for focusing the picosecond pulse light after splitting into one on a photodiode light sensing surface of a photoelectric detection module in the photoelectric detector. The second lens is used for focusing the picosecond pulse light after splitting into another on another photodiode light sensing surface of the photoelectric detection module in the photoelectric detector. The photoelectric detector is used for sending the generated AC voltage signal at the resonance frequency to the spectrum analyzer for noise characteristic analysis, and sending the generated DC voltage signal to the oscilloscope for balance analysis of the photoelectric detector.

[0009] According to the specific embodiments of the present application, the following technical effects are disclosed:

[0010] The resonant balanced zero beat photoelectric detector with the notch characteristic, the printing device and the testing device provided by the embodiment of the present application introduce the LC series resonance notch circuit in the resonant balanced zero beat detector, and the noise at the pulse light repetition frequency can be suppressed by adjusting the trimmer capacitor in the LC series resonance notch circuit, so that the best notch effect is ensured, and the saturation power and the signal-to-noise ratio of the photoelectric detector under the pulse light are improved. BRIEF DESCRIPTION OF DRAWINGS

[0011] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0012] Figure 1 A circuit schematic diagram of a photoelectric detector provided for the embodiment 1 of the present application.

[0013] Figure 2 A structure schematic diagram of a photoelectric detector testing device provided for the embodiment 3 of the present application.

[0014] Figure 3 A comparison diagram of notch effects provided for the embodiment 3 of the present application.

[0015] Figure 4 The graph shows the signal-to-noise ratio and saturation power results of the photodetector provided in Embodiment 3 of the present invention. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] In quantum experiments, the high energy at the repetition frequency of pulsed light can easily cause circuit saturation and even damage to electronic components. Therefore, in photodetection, it is difficult to improve the signal-to-noise ratio (SNR) of the detector to meet the requirements of photodetection. This invention develops a unique photodetector with an LC resonant notch filter circuit structure to suppress noise at the pulse repetition frequency and improve the saturation power and SNR of the photodetector. Experimental results show that by fine-tuning the adjustable capacitance parameters of the LC resonant notch filter to optimize the notch effect, the pulse at the repetition frequency is suppressed by 28.68 dB. The saturation power of the photodetector is increased to 12 mW, and the SNR is increased to 19.60 dB, basically meeting the requirements of photodetectors in squeezed state generation applications.

[0018] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] Example 1

[0020] like Figure 1 As shown, a resonant balanced zero-beat photodetector with notch characteristics in this embodiment includes: a photodetector module, an LC series resonant notch circuit, a first-stage resonant frequency selective amplifier circuit, a second-stage frequency selective network, an AC amplifier module, and a DC amplifier module.

[0021] The photoelectric detection module is used for converting the optical signal into an electrical signal to generate a photoelectric current difference signal; the LC series resonance trap circuit comprises a first inductor and a trimmer capacitor; one end of the trimmer capacitor is connected to one end of the first inductor, and the other end of the trimmer capacitor is grounded; the other end of the first inductor is connected between the photoelectric detection module and the first-stage resonant type frequency selection and amplification circuit in the resonant type balanced homodyne detector; the LC series resonance trap circuit is used for filtering out the signal at the pulse laser repetition frequency in the photoelectric current difference signal detected by the photoelectric detection module by adjusting the capacitance value of the trimmer capacitor, and sending the filtered photoelectric current difference signal to the first-stage resonant type frequency selection and amplification circuit; the output end of the first-stage resonant type frequency selection and amplification circuit is connected to the input end of the second-stage frequency selection network and the input end of the direct current amplification module; the first-stage resonant type frequency selection and amplification circuit is used for converting the filtered photoelectric current difference signal into a first-stage voltage signal at the resonant frequency, and amplifying the filtered photoelectric current difference signal; the output end of the second-stage frequency selection network is connected to the first input end of the alternating current amplification module; the second-stage frequency selection network is used for performing second-stage frequency selection on the first-stage voltage signal at the resonant frequency to obtain a second-stage voltage signal at the resonant frequency, and simultaneously transmitting the second-stage voltage signal at the resonant frequency to the alternating current amplification module; the alternating current amplification module is used for amplifying the second-stage voltage signal at the resonant frequency to generate an alternating current voltage signal at the resonant frequency; and the direct current amplification module is used for filtering out a direct current voltage signal from the first-stage voltage signal at the resonant frequency, and amplifying the filtered direct current voltage signal.

[0022] In one example, the photoelectric detection module comprises: a pair of series-connected photodiodes and a corresponding power supply module. The middle connection point A of the pair of series-connected photodiodes is connected to the other end of the first inductor. The pair of series-connected photodiodes are connected to the power supply device at both ends.

[0023] The LC series passive trap is composed of an inductor L and a capacitor C connected in series to ground. Since the inductor has the function of passing low frequency and blocking high frequency, and the capacitor has the function of passing high frequency and blocking low frequency. When LC resonates, the circuit only allows signals at the resonant frequency to pass, so signals at specific frequencies are suppressed.

[0024] The first-stage resonant type frequency selection and amplification circuit comprises: a resonant transimpedance structure and a first operational amplifier. The input end of the resonant transimpedance structure and the first input end of the first operational amplifier are both connected to the other end of the first inductor, and the second input end of the first operational amplifier is grounded; the output end of the resonant transimpedance structure and the output end of the first operational amplifier are both connected to the input end of the second-stage frequency selection network and the input end of the direct current amplification module; the resonant transimpedance structure is used for converting the filtered photoelectric current difference signal through the LC series resonance trap circuit into a first-stage voltage signal at the resonant frequency. The first operational amplifier is used for amplifying the filtered photoelectric current difference signal through the LC series resonance trap circuit.

[0025] The resonance trans-impedance structure comprises a second inductor, a first resistor, a first capacitor and a second resistor. The second inductor is connected in series with the first resistor, and then connected in parallel with the first capacitor and the second resistor respectively. One end of the parallel connection is connected to the other end of the first inductor, and the other end of the parallel connection is connected to the input end of the second-order frequency selection network and the input end of the direct current amplification module respectively.

[0026] The first inductor is L1 in Figure 1 , the fine tuning capacitor is C1 in Figure 1 , the second inductor is L2 in Figure 1 , the first resistor is R1 in Figure 1 , the first capacitor is C2 in Figure 1 , and the second resistor is Rf in Figure 1 . The model of the first operational amplifier is OPA690.

[0027] In another example, the second-order frequency selection network comprises a third inductor, a second capacitor and a third resistor. One end of the third inductor is connected to the output end of the first-order frequency selection network, and the other end of the third inductor is connected to one end of the second capacitor. The other end of the second capacitor is connected to one end of the third resistor and the first input end of the alternating current amplification module respectively. The other end of the third resistor is grounded. The second-order frequency selection network is used to perform second-order frequency selection on the amplified photoelectric current difference signal to obtain a second-order voltage signal at the resonance frequency, and simultaneously transmit the second-order voltage signal at the resonance frequency to the alternating current amplification module.

[0028] The third inductor is L3 in Figure 1 , the second capacitor is C3 in Figure 1 , and the third resistor is R2 in Figure 1 . The model of the second operational amplifier is LMH6624. One end of a resistor R4 and one end of a resistor R5 are connected to the second input end of the second operational amplifier. The other end of the resistor R4 is connected to the output end of the second operational amplifier, and the other end of the resistor R5 is grounded.

[0029] The alternating current amplification module comprises a second operational amplifier, a fourth resistor and a fifth resistor. The first input end of the second operational amplifier is connected to the output end of the second-order frequency selection network. The other input end of the second operational amplifier is connected to one end of the fourth resistor and one end of the fifth resistor. The other end of the fifth resistor is grounded, and the output end of the second operational amplifier is connected to the other end of the fourth resistor. The output end of the second operational amplifier and the other end of the fourth resistor are connected to a 50 Ω resistor to serve as the alternating current output signal of the photoelectric detector. The resistance ratio of the fourth resistor and the fifth resistor determines the amplification multiple of the alternating current amplification module. The alternating current amplification module is used to amplify the second-order voltage signal at the resonance frequency to generate an alternating current voltage signal at the resonance frequency.

[0030] Still referring to Figure 1The DC amplification module includes a DC filter circuit and a DC amplification circuit. The input terminal of the DC filter circuit is connected to the output terminal of the first-stage resonant frequency-selective amplifier circuit and the input terminal of the second-stage frequency-selective network. The output terminal of the DC filter circuit is connected to the input terminal of the DC amplification circuit. The DC filter circuit is used to filter high-frequency signals and select the DC signal. The input terminal of the DC amplification circuit is connected to the output terminal of the DC filter circuit, and a 50Ω resistor is connected to the output terminal of the DC amplification circuit as the DC output of the photodetector. The DC amplification circuit amplifies the DC signal selected by the DC filter circuit and outputs it as a DC voltage signal.

[0031] The DC filter circuit includes a sixth resistor and a third capacitor. One end of the sixth resistor is connected to the output of the first-stage frequency selection network and the input of the second-stage frequency selection network, respectively. The other end of the sixth resistor is connected to one end of the third capacitor and the input of the DC voltage amplifier circuit, respectively. The other end of the third capacitor is grounded.

[0032] The DC amplifier circuit includes a third operational amplifier, a seventh resistor, and an eighth resistor. The first input terminal of the third operational amplifier is connected to the output terminal of the sixth resistor. The other input terminal of the third operational amplifier is connected to one end of the seventh resistor and one end of the eighth resistor. The output terminal of the third operational amplifier is connected to the other end of the seventh resistor, and the other end of the eighth resistor is grounded. The third operational amplifier amplifies the DC signal after passing through the DC filter circuit, generating a DC voltage signal. The resistance ratio of the seventh and eighth resistors determines the amplification factor of the DC amplifier circuit.

[0033] The sixth resistor is Figure 1 R3 in the middle, the third capacitor is Figure 1 C4 in the diagram, the third operational amplifier is model OP27, and the seventh resistor is... Figure 1 R6 in the middle, the eighth resistor is Figure 2 R7 in the middle.

[0034] The photodetector of this invention comprises a photodetector section, a resonant notch filter section, a two-stage frequency selection network, an AC voltage amplification section, and a DC voltage amplification section. In this device, the photocurrents generated by the two photodiodes are subtracted at node A, generating a photocurrent difference signal. This photocurrent difference signal contains shot noise at the resonant frequency and laser noise at the pulse repetition frequency. This signal is filtered out at the pulse repetition frequency by an LC series resonant notch filter network before entering the frequency selection network. The resonant transimpedance structure replaces the traditional transimpedance TIA structure, which has the advantage of simultaneously performing amplification and first-stage frequency selection. The weak photocurrent signal is converted into a voltage signal at the resonant frequency and amplified by the resonant transimpedance section. The voltage signal then undergoes second-stage frequency selection and voltage amplification.

[0035] The photocurrent difference signal is converted into a voltage signal of a specific frequency by a resonant transimpedance part, and the voltage signal is amplified by an operational amplifier, the resonant transimpedance part is composed of L2, C2, R1 and Rf, L2 is selected as 4.7 uH, C2 is selected as 10 pF, R1 is 50 Omega, and Rf is 5000 Omega, and finally a resonant impedance of 3000 Omega is obtained to convert the weak photocurrent difference signal into a voltage signal large enough. L3, C3 and R2 form a series resonant network for secondary frequency selection, L3 is 1 uH, C3 is 68 pF, and R2 is 50 Omega, and the voltage signal after two-stage frequency selection is amplified by two-stage voltage amplifier LMH6624 (TI Company) with an amplification factor A u determined by R4 and R5 together, The final AC signal is impedance matched through a 50 Omega resistor and connected to a spectrum analyzer for noise characteristic analysis. R3 and C4 here play the role of separating AC and DC, filtering out the DC signal and amplifying it through the voltage amplifier composed of operational amplifier OP27 and R6, R7.

[0036] Because the inductance L1 and the capacitance C1 of the resonant notch part have a great influence on electronic noise, and their numerical accuracy also has a great influence on the notch effect, the capacitor and inductor components are carefully selected in the application, and finally an inductance L1 of 820 nH and a capacitance C1 of 4.9 pF are selected. A 2.5 pF-6 pF trimmer capacitor is used instead of the capacitor, and the trimmer capacitor can better select the appropriate notch frequency and good notch depth.

[0037] Example 2

[0038] In order to apply the photoelectric detector corresponding to the above-mentioned embodiment 1 to realize the corresponding function and technical effect, a photoelectric detector printing device is provided below, the printing device comprises: a printed circuit board, an aluminum metal shell and the photoelectric detector of embodiment 1.

[0039] The photoelectric detector is printed on the printed circuit board; the printed circuit board printed with the photoelectric detector is sealed in the aluminum metal shell.

[0040] The reasonable layout of the PCB (Printed Circuit Board) is very important in realizing stable circuit performance, especially in high-frequency signal applications. All the wires around the operational amplifier should be as short as possible, the wires near the resonant circuit should be as short as possible to reduce the influence of parasitic capacitance, the two photodiodes are back to the board, and the power lines and signal lines are respectively on the top layer and the bottom layer to avoid electromagnetic wave interference. The prepared detector circuit board is sealed in an aluminum metal shell to reduce the interference of external electromagnetic waves and ensure that the detector can work normally.

[0041] Embodiment 3

[0042] The photoelectric detector testing device according to the embodiment of the present application comprises a laser source, a half-wave plate, a polarization beam splitter prism, a first mirror, a second mirror, a first lens, a second lens, a spectrum analyzer, an oscilloscope and the photoelectric detector of the embodiment 1. Figure 2 As shown in the figure, the testing device comprises a laser source, a half-wave plate, a polarization beam splitter prism, a first mirror, a second mirror, a first lens, a second lens, a spectrum analyzer, an oscilloscope and the photoelectric detector of the embodiment 1.

[0043] The AC voltage output end of the photoelectric detector is connected with the spectrum analyzer, and the DC voltage output end of the photoelectric detector is connected with the oscilloscope. The laser source is used to generate picosecond pulse light with a repetition frequency. The picosecond pulse light is transmitted to the polarization beam splitter prism after passing through the half-wave plate. The polarization beam splitter prism is used to divide the picosecond pulse light into two beams, one of which is reflected to the first lens through the first mirror, and the other of which is reflected to the second lens through the second mirror. The first lens is used to focus the picosecond pulse light after the division on one photodiode light-sensing surface of the photoelectric detection module in the photoelectric detector. The second lens is used to focus the picosecond pulse light after the division on another photodiode light-sensing surface of the photoelectric detection module in the photoelectric detector. The photoelectric detector is used to send the generated AC voltage signal at the resonance frequency to the spectrum analyzer for noise characteristic analysis, and send the generated DC voltage signal to the oscilloscope for balance analysis of the photoelectric detector.

[0044] Figure 3 In the figure, Laser represents the laser source, HWP represents the half-wave plate, PBS represents the polarization beam splitter prism, M1 represents the first mirror, M2 represents the second mirror, L1 represents the first lens, L2 represents the second lens, PD1 and PD2 represent a pair of photodiodes, DC represents the DC voltage signal, AC represents the AC voltage signal, OSC represents the oscilloscope, and SA represents the spectrum analyzer.

[0045] The photoelectric detector testing device according to the embodiment of the present application can test the performance of the notch part of the photoelectric detector.

[0046] The testing experiment is described as follows:

[0047] After the picosecond pulse light with a repetition frequency of 80 MHz is divided by 50:50 through the half-wave plate and the PBS, the light is focused on the light-sensing surfaces of the photodiodes PD1 and PD2 through the two lenses L1 and L2 with a focal length of 50 mm. The response of the two photodiode probes is balanced by rotating the half-wave plate to change the splitting ratio of the PBS. The DC and AC outputs of the detector are connected to the oscilloscope and the spectrum analyzer respectively to test the performance of the detector.

[0048] Experimental test results:

[0049] The present application firstly tests the performance of the notch part of the detector, under the total optical power of 0.5 mW, 0.25 mW on both sides, the present application blocks one side of the detector, only single side works, and tests the notch effect. Figure 3 As shown in the figure, the red curve is the single side pulse tested without adding the notch circuit, the height of the pulse is 57.68 dB. When the detector has the notch circuit for notch operation, the pulse height is only 29.00 dB, it can be clearly seen that the pulse at 80 MHz is well suppressed, the experiment successfully obtains the notch effect of 28.68 dB, and the structure plays a great role in improving the saturation optical power and the signal-to-noise ratio.

[0050] Figure 4 The black curve in the figure is the electronic noise without the notch circuit, the red curve is the 80 MHz pulse when only single side works without the notch circuit, the green curve is the electronic noise with the notch circuit, and the blue curve is the 80 MHz pulse after the notch. Using the Agilent spectrum analyzer, the RBW is 100 kHz, the VBW is 100 Hz, and the scanning time is 400 ms.

[0051] ​ The test results of the signal-to-noise ratio characteristics and the saturation power of the detector. Since the notch circuit effectively suppresses the laser repetition frequency, it reduces the saturation effect caused by high energy at the laser repetition frequency. Finally, the saturation optical power of the detector reaches 12 mW and the signal-to-noise ratio reaches 19.60 dB.

[0052] The technical features of the above embodiments can be combined arbitrarily, in order to make the description concise, not all possible combinations of the technical features in the above embodiments are described, however, as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the present application.

[0053] The principles and implementation modes of the present application are described by applying specific examples in this paper, the above embodiment is only used to help understand the method of the present application and its core idea; at the same time, for those skilled in the art, according to the idea of the present application, the specific implementation mode and application range will be changed. In conclusion, the content of the specification should not be understood as the limitation of the present application.

Claims

1. A resonant balanced homodyne photodetector with a notch characteristic, characterized in that, The application relates to a photoelectric detection module, an LC series resonant notch circuit, a primary resonant type frequency selection and amplification circuit, a secondary frequency selection network, an alternating current amplification module and a direct current amplification module. The photoelectric detection module is used for converting an optical signal into an electric signal and generating a photoelectric current difference signal. The LC series resonant notch circuit comprises a first inductor and a trimming capacitor; one end of the trimming capacitor is connected with one end of the first inductor, and the other end of the trimming capacitor is grounded; the other end of the first inductor is connected between the photoelectric detection module and the primary resonant type frequency selection and amplification circuit in the resonant type balanced zero beat detector. The LC series resonant notch circuit is used for filtering the signal at the pulse laser repetition frequency in the photoelectric current difference signal detected by the photoelectric detection module by adjusting the capacitance value of the trimming capacitor, and sending the filtered photoelectric current difference signal into the primary resonant type frequency selection and amplification circuit. The output end of the primary resonant type frequency selection and amplification circuit is connected with the input end of the secondary frequency selection network and the input end of the direct current amplification module; the primary resonant type frequency selection and amplification circuit is used for converting the filtered photoelectric current difference signal into a primary voltage signal at a resonant frequency and amplifying the filtered photoelectric current difference signal. The output end of the secondary frequency selection network is connected with the first input end of the alternating current amplification module; the secondary frequency selection network is used for performing secondary frequency selection on the primary voltage signal at the resonant frequency to obtain a secondary voltage signal at the resonant frequency, and simultaneously transmitting the secondary voltage signal at the resonant frequency to the alternating current amplification module. The alternating current amplification module is used for amplifying the secondary voltage signal at the resonant frequency to generate an alternating current voltage signal at the resonant frequency. The direct current amplification module is used for filtering a direct current voltage signal from the primary voltage signal at the resonant frequency and amplifying the filtered direct current voltage signal. The photoelectric detection module comprises a pair of series-connected photoelectric diodes and a power supply device.

2. The resonant balanced homodyne photodetector with a notch characteristic according to claim 1, characterized in that, The middle connecting point of the pair of series-connected photoelectric diodes is connected with the other end of the first inductor. The two ends of the pair of series-connected photoelectric diodes are connected with the power supply device. The primary resonant type frequency selection and amplification circuit comprises a resonant trans-impedance structure and a first operational amplifier.

3. The resonant balanced homodyne photodetector with notch characteristics according to claim 1, characterized in that, The input end of the resonant trans-impedance structure and the first input end of the first operational amplifier are both connected with the other end of the first inductor, and the second input end of the first operational amplifier is grounded; the output end of the resonant trans-impedance structure and the output end of the first operational amplifier are both connected with the input end of the secondary frequency selection network and the input end of the direct current amplification module. The resonant trans-impedance structure is used for converting the filtered photoelectric current difference signal into a primary voltage signal at a resonant frequency. The first operational amplifier is used for amplifying the filtered photoelectric current difference signal. The resonant trans-impedance structure comprises a second inductor, a first resistor, a first capacitor and a second resistor.

4. The resonant balanced homodyne photodetector with a notch characteristic according to claim 3, characterized in that, The second inductor and the first resistor are connected in series, and then connected in parallel with the first capacitor and the second resistor; one end of the parallel connection is connected with the other end of the first inductor, and the other end of the parallel connection is connected with the input end of the secondary frequency selection network and the input end of the direct current amplification module. The secondary frequency selection network comprises a third inductor, a second capacitor and a third resistor.

5. The resonant balanced homodyne photodetector with notch characteristics according to claim 1, characterized in that, ​ One end of the third inductor is connected with the output end of the first frequency selection network, and the other end of the third inductor is connected with one end of the second capacitor; the other end of the second capacitor is connected with one end of the third resistor and the first input end of the alternating current amplification module respectively; the other end of the third resistor is grounded.

6. The resonant balanced homodyne photodetector with notch characteristics according to claim 1, characterized in that, The alternating current amplification module comprises a second operational amplifier, a fourth resistor and a fifth resistor; The first input end of the second operational amplifier is connected with the output end of the second frequency selection network, and the other input end of the second operational amplifier is connected with one end of the fourth resistor and one end of the fifth resistor; the output end of the second operational amplifier is connected with the other end of the fourth resistor, and the other end of the fifth resistor is grounded; The second operational amplifier is used for amplifying the second voltage signal at the resonant frequency to generate an alternating current voltage signal at the resonant frequency.

7. The resonant balanced homodyne photodetector with notch characteristics according to claim 1, characterized in that, The direct current amplification module comprises a direct current filter circuit and a direct current amplification circuit; The direct current filter circuit comprises a sixth resistor and a third capacitor; one end of the sixth resistor is connected with the output end of the first resonant frequency selection amplification circuit and the input end of the second frequency selection network respectively, and the other end of the sixth resistor is connected with one end of the third capacitor and the input end of the direct current voltage amplification circuit respectively; the other end of the third capacitor is grounded; The direct current filter circuit is used for filtering high frequency signals in the first voltage signal at the resonant frequency to select a direct current signal; The direct current amplification circuit is used for amplifying the direct current signal selected after the direct current filter circuit and outputting as a direct current voltage signal.

8. The resonant balanced homodyne photodetector with a notch characteristic according to claim 7, characterized in that, The direct current amplification circuit comprises a third operational amplifier, a seventh resistor and an eighth resistor; The first input end of the third operational amplifier is connected with the other end of the sixth resistor, and the other input end of the third operational amplifier is connected with one end of the seventh resistor and one end of the eighth resistor; the output end of the third operational amplifier is connected with the other end of the seventh resistor, and the other end of the eighth resistor is grounded; The third operational amplifier is used for amplifying the direct current signal after the direct current filter circuit to generate a direct current voltage signal.

9. A resonant balanced zero-biased photodetector printed device with notch characteristics, characterized in that, The printing device comprises a printed circuit board, an aluminum metal shell and the resonant balanced zero beat photodetector with the notch characteristic according to any one of claims 1-8. The resonant balanced zero beat photodetector with the notch characteristic is printed on the printed circuit board; the printed circuit board printed with the photodetector is sealed in the aluminum metal shell.

10. A test device for a resonant balanced zero-beat photodetector with notch characteristics, characterized in that, The testing device comprises a laser source, a half wave plate, a polarization beam splitter prism, a first reflector, a second reflector, a first lens, a second lens, a spectrum analyzer, an oscilloscope and the photodetector according to any one of claims 1-8. The alternating current voltage output end of the photodetector is connected with the spectrum analyzer, and the direct current voltage output end of the photodetector is connected with the oscilloscope. The laser source is used for generating picosecond pulse light with a repetition frequency; the picosecond pulse light is transmitted to the polarization beam splitter prism after passing through the half wave plate; The polarization beam splitter prism is used for splitting the picosecond pulse light into two beams, one of which is reflected to the first lens through the first reflector, and the other of which is reflected to the second lens through the second reflector; The first lens is used for focusing the picosecond pulse light after splitting into one of the photodiode light sensing surfaces of the photodetection module of the photodetector; The second lens is used for focusing the picosecond pulse light after splitting into the other of the photodiode light sensing surfaces of the photodetection module of the photodetector. The second lens is used for focusing another split picosecond pulse light to another photodiode photosensitive surface of the photodetection module in the photodetector; The photodetector is used for sending the generated alternating voltage signal at the resonance frequency to a spectrum analyzer for noise characteristic analysis, and sending the generated direct current voltage signal to an oscilloscope for balance analysis of the photodetector.

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