High-speed, low-noise laser signal detection apparatus

Abstract

A high-speed, low-noise laser signal detection apparatus, comprising a low-noise linear regulated power supply and a laser detection processing module. The low-noise linear regulated power supply (01-03) comprises an isolation unit (01), a voltage regulation and filtering unit (02), and a reference unit (03). The laser detection processing module (04-09) comprises a laser light signal detection input unit (05), a bias unit (04), a differential amplification unit (07), an active filtering unit (08), and an output interface unit (09). An output end of the voltage regulation and filtering unit (02) is connected to the reference unit (03) and the laser detection processing module (04-09). The reference unit (03) is connected to the bias unit (04) and is configured to provide a reference voltage to the bias unit (04). The bias unit (04) is configured to provide a bias voltage to the differential amplification unit (07). The differential amplification unit (07) comprises a multi-stage in-phase proportional differential amplification circuit, and the active filtering unit (08) comprises a multi-order active low-pass filter. According to the high-speed, low-noise laser signal detection apparatus, the detection bandwidth of a laser signal can be expanded, the signal-to-noise ratio of high-frequency pulse measurement can be reduced, and the anti-interference characteristics of a power supply can be improved.

Description

High-speed low-noise laser signal detection device

[0001] Cross-reference to related applications

[0002] The present application claims priority to the Chinese patent application No. 2024108138047, filed on June 24, 2024, entitled "High-speed low-noise laser signal detection device", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present application relates to the technical field of laser signal detection, in particular to a high-speed low-noise laser signal detection device. BACKGROUND

[0004] The existing laser signal detection device has a maximum bandwidth of 100MHz for laser measurement, and a measurement noise of 10PW / HZ. Most of them are powered by battery or switching power supply.

[0005] The above-mentioned prior art has the following disadvantages: the high-frequency pulse detection bandwidth is limited; the high-frequency pulse measurement signal-to-noise ratio is poor; the long-time power supply voltage is unstable or there is power supply interference.

[0006] SUMMARY

[0007] The purpose of the present application is to solve the problems of limited high-frequency pulse detection bandwidth, poor high-frequency pulse measurement signal-to-noise ratio, and unstable long-time power supply voltage or power supply interference of the existing laser signal detection device.

[0008] To solve the above-mentioned problems, the present application provides a high-speed low-noise laser signal detection device, which comprises a low-noise linear voltage stabilizing power supply and a laser detection processing module; the low-noise linear voltage stabilizing power supply comprises an isolation unit, a voltage stabilizing filter unit and a reference unit; the laser detection processing module comprises a laser optical signal detection input unit, a bias voltage unit, a differential amplification unit, an active filter unit and an output interface unit; the output end of the voltage stabilizing filter unit is connected with the reference unit and the laser detection processing module, and is configured to supply power to the reference unit, the differential amplification unit and the active filter unit; the reference unit is connected with the bias voltage unit, and is configured to provide a reference voltage to the bias voltage unit, and the bias voltage unit is configured to provide a bias voltage to the differential amplification unit; the differential amplification unit comprises a multi-stage in-phase proportional differential amplification circuit, and the active filter unit comprises a multi-order active low-pass filter.

[0009] Optionally, the multi-stage same-phase proportional differential amplification circuit comprises a first radio frequency operational amplifier, a second radio frequency operational amplifier and a third radio frequency operational amplifier; the same-phase input end of the first radio frequency operational amplifier is connected to the laser light signal detection input unit, and the opposite-phase input end is connected to the opposite-phase input end of the second radio frequency operational amplifier; the same-phase input end of the second radio frequency operational amplifier is connected to the bias voltage output port of the bias voltage unit; the output end of the first radio frequency operational amplifier is connected to the same-phase input end of the third radio frequency operational amplifier, and the output end of the second radio frequency operational amplifier is connected to the opposite-phase input end of the third radio frequency operational amplifier; and the output end of the third radio frequency operational amplifier is connected to the active filter unit.

[0010] Optionally, the opposite-phase input end of the first radio frequency operational amplifier is connected to the output end through a first resistor; the opposite-phase input end of the second radio frequency operational amplifier is connected to the output end through a second resistor; the same-phase input end of the third radio frequency operational amplifier is grounded through a third resistor; and the output end of the third radio frequency operational amplifier is connected to the active filter unit through a fourth resistor.

[0011] Optionally, the multi-stage active low-pass filter is a second-order Butterworth active filter; the second-order Butterworth active filter comprises an operational amplifier, a fourth resistor, a fifth resistor, a first capacitor and a second capacitor; the positive power input end of the operational amplifier is connected to the positive voltage DC output end of the voltage stabilizing filter unit, and the negative power input end is connected to the negative voltage DC output end of the voltage stabilizing filter unit; the fourth resistor and the fifth resistor are connected between the output end of the multi-stage same-phase proportional differential amplification circuit and the same-phase input end of the operational amplifier; one end of the first capacitor is connected between the fourth resistor and the fifth resistor, and the other end is connected to the opposite-phase input end of the operational amplifier; one end of the second capacitor is connected between the fifth resistor and the same-phase input end of the operational amplifier, and the other end is connected to the same-phase input end of the operational amplifier.

[0012] Optionally, the laser light signal detection input unit comprises a photodiode and a zero-setting potentiometer; one end of the zero-setting potentiometer is connected to the reference unit, and the other end is connected to the negative electrode of the photodiode; the positive electrode of the photodiode is connected to the same-phase input end of the first radio frequency operational amplifier and grounded through an RC filter circuit; and the photodiode is configured to receive a laser signal to be detected.

[0013] Optionally, the isolation unit is a linear low-frequency isolation transformer.

[0014] Optionally, the voltage stabilizing filter unit comprises a full-wave rectification filter circuit and a voltage stabilizing filter circuit; the voltage stabilizing filter circuit comprises a three-terminal voltage stabilizer, a third capacitor and a fourth capacitor; the input end of the three-terminal voltage stabilizer is connected to the output end of the full-wave rectification filter circuit, and the third capacitor and the fourth capacitor are connected in parallel and connected between the output end and the ground end of the three-terminal voltage stabilizer.

[0015] Optionally, the reference unit is a precision voltage reference unit or a precision current reference unit.

[0016] Optionally, the multi-stage in-phase proportional differential amplification circuit is two-stage, three-stage or four-stage; or, the multi-order active low-pass filter is two-order, three-order or four-order.

[0017] Optionally, the laser detection processing module further comprises a coaxial output unit; the coaxial output unit is connected with the multi-order active low-pass filter and is configured to output a laser signal detection result signal.

[0018] The high-speed low-noise laser signal detection device provided by the embodiment of the present application can expand the detection bandwidth of the laser signal, reduce the signal-to-noise ratio of high-frequency pulse measurement, and improve the anti-interference characteristics of the power supply. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed to be used in the embodiment or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only embodiments of the present application, and those skilled in the art can obtain other drawings according to the provided drawings without creative labor.

[0020] Fig. 1 is a principle block diagram of the high-speed low-noise laser signal detection device provided by the embodiment of the present application;

[0021] Fig. 2 is a circuit diagram of the high-speed low-noise laser signal detection device provided by the embodiment of the present application. DETAILED DESCRIPTION

[0022] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the drawings. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0023] The embodiment of the present application provides a high-speed low-noise laser signal detection device, which can expand the detection bandwidth of the laser signal, reduce the signal-to-noise ratio of high-frequency pulse measurement, and improve the anti-interference characteristics of the power supply. Exemplarily, the 2um laser measurement bandwidth is expanded from the existing 100Mhz to 500Mhz, and the measurement noise is reduced from the existing 10PW / HZ to below 0.1PW / HZ.

[0024] The high-speed low-noise laser signal detection device provided by the embodiment of the present application comprises a low-noise linear voltage stabilizing power supply and a laser detection processing module.

[0025] The low-noise linear voltage stabilizing power supply comprises an isolation unit, a voltage stabilizing filter unit and a reference unit, and is configured to provide a long-term stable and reliable low-noise power supply. The laser detection processing module comprises a laser light signal detection input unit, a bias unit, a differential amplification unit, an active filter unit and an output interface unit, and can be applied to a larger laser detection bandwidth and has lower measurement noise.

[0026] Specifically, the output end of the voltage stabilizing filter unit is connected with the reference unit and the laser detection processing module, and is configured to supply power to the reference unit, the differential amplification unit and the active filter unit. The voltage stabilizing filter unit functions to rectify, filter and linearly stabilize, thereby providing a low-noise power supply for the detection circuit.

[0027] The reference unit is connected with the bias unit and is configured to provide a reference voltage to the bias unit, which in turn provides a bias voltage to the differential amplification unit. The reference unit can provide a high-precision reference voltage for the detection circuit. The bias unit can provide a bias voltage for the differential amplification unit.

[0028] The differential amplification unit comprises a multi-stage same-phase proportional differential amplification circuit, and the active filter unit comprises a multi-order active low-pass filter.

[0029] By way of example, the multi-stage same-phase proportional differential amplification circuit can be a same-phase proportional differential amplification circuit composed of radio frequency operational amplifiers, which has a high common-mode rejection ratio and can amplify the laser detection signal by a high multiple. The multi-order active low-pass filter can filter out noise frequencies above a high frequency (e.g. 800 MHZ). Optionally, the multi-stage same-phase proportional differential amplification circuit is a two-stage, three-stage or four-stage same-phase proportional differential amplification circuit, and the multi-order active low-pass filter is a two-order, three-order or four-order active low-pass filter.

[0030] Optionally, the multi-stage same-phase proportional differential amplification circuit comprises a first radio frequency operational amplifier, a second radio frequency operational amplifier and a third radio frequency operational amplifier. The same-phase input end of the first radio frequency operational amplifier is connected with the laser light signal detection input unit, and the opposite-phase input end is connected with the opposite-phase input end of the second radio frequency operational amplifier. The same-phase input end of the second radio frequency operational amplifier is connected with the bias voltage output port of the bias unit. The output end of the first radio frequency operational amplifier is connected with the same-phase input end of the third radio frequency operational amplifier, and the output end of the second radio frequency operational amplifier is connected with the opposite-phase input end of the third radio frequency operational amplifier. The output end of the third radio frequency operational amplifier is connected with the active filter unit.

[0031] Further, the opposite-phase input end of the first radio frequency operational amplifier is connected to the output end through a first resistor, the opposite-phase input end of the second radio frequency operational amplifier is connected to the output end through a second resistor, the same-phase input end of the third radio frequency operational amplifier is grounded through a third resistor, and the output end of the third radio frequency operational amplifier is connected to the active filter unit through a fourth resistor.

[0032] The first radio frequency operational amplifier, the second radio frequency operational amplifier and the third radio frequency operational amplifier form a same-phase proportional differential amplification loop, which greatly improves the common-mode rejection ratio and performs high-multiple two-stage amplification on the detection signal, and then outputs the detection signal to the subsequent active filter unit.

[0033] Optionally, the multi-stage active low-pass filter is a second-order Butterworth active filter; the second-order Butterworth active filter comprises an operational amplifier, a fourth resistor, a fifth resistor, a first capacitor and a second capacitor.

[0034] The positive power input terminal of the operational amplifier is connected to the positive voltage DC output terminal of the voltage stabilizing filter unit, and the negative power input terminal is connected to the negative voltage DC output terminal of the voltage stabilizing filter unit; the fourth resistor and the fifth resistor are connected between the output terminal of the multi-stage same-phase proportional differential amplification circuit and the same-phase input terminal of the operational amplifier; one end of the first capacitor is connected between the fourth resistor and the fifth resistor, and the other end is connected to the inverse-phase input terminal of the operational amplifier; one end of the second capacitor is connected between the fifth resistor and the same-phase input terminal of the operational amplifier, and the other end is grounded.

[0035] The operational amplifier, the resistor and the capacitor can form a second-order active filter to filter out high-frequency noise above 800M, and then output.

[0036] Further, the laser light signal detection input unit can further comprise a photo-diode (PD) and a zero-adjusting potentiometer; one end of the zero-adjusting potentiometer is connected to the reference unit, and the other end is connected to the negative electrode of the photo-diode; the positive electrode of the photo-diode is connected to the same-phase input terminal of the first radio frequency operational amplifier and grounded through an RC filter circuit; the photo-diode is configured to receive the laser signal to be detected.

[0037] The zero-adjusting potentiometer can make the circuit zero-output when detecting the ambient free-space light.

[0038] Exemplarily, the isolation unit is a linear low-frequency isolation transformer, which can reduce the input of high-frequency noise.

[0039] Exemplarily, the voltage stabilizing filter unit comprises a full-wave rectification filter circuit and a voltage stabilizing filter circuit; the voltage stabilizing filter circuit comprises a three-terminal voltage stabilizer, a third capacitor and a fourth capacitor; the input terminal of the three-terminal voltage stabilizer is connected to the output terminal of the full-wave rectification filter circuit, and the third capacitor and the fourth capacitor are connected in parallel and connected between the output terminal and the ground terminal of the three-terminal voltage stabilizer.

[0040] Optionally, the reference unit is a precision voltage reference unit or a precision current reference unit, which provides a high-precision reference voltage or reference current for the detection circuit.

[0041] Optionally, the laser detection processing module further comprises a coaxial output unit, which is a connection between the detection device and an external device. One end of the coaxial output unit is connected with the multi-stage active low-pass filter, and the other end is connected with the external device, so as to output the signal detection result to the external device. Exemplarily, the coaxial output unit can adopt a 50-ohm coaxial cable or a 75-ohm coaxial cable, and the impedances thereof are 50 ohm and 75 ohm respectively.

[0042] Fig. 1 shows a principle block diagram of a high-speed low-noise laser signal detection device provided by an embodiment of the present application. Exemplarily, the units are specifically described as follows:

[0043] The isolation unit is a linear low-frequency isolation transformer, which can reduce the input of high-frequency noise.

[0044] The voltage stabilizing filter unit is a rectification filter and a linear voltage stabilizer, which provides a low-noise power supply for the detection circuit.

[0045] The reference unit provides a high-precision reference voltage for the detection circuit.

[0046] The bias unit provides a bias voltage for the differential proportional amplifier.

[0047] The laser detection inlet is a laser signal detection input end and a PD probe input end.

[0048] The zero adjustment unit can make the circuit zero output when detecting the ambient free space light.

[0049] The differential amplification unit is a same-phase proportional differential amplification circuit composed of a radio frequency operational amplifier, which has a high common-mode rejection ratio and performs high-multiple proportional amplification on the laser detection signal.

[0050] The filter unit adopts a second-order Butterworth (Q=0.707) active filter to filter out noise frequencies above 800 MHZ.

[0051] The output interface unit is a laser detection amplification signal output end, which can adopt a 50-ohm coaxial output.

[0052] Fig. 2 shows a circuit diagram of a high-speed low-noise laser signal detection device provided by an embodiment of the present application. In the specific implementation, the device is composed of a "low-noise linear voltage stabilizer" (dashed box 01-03) and a "laser detection processing module" (dashed box 04-09).

[0053] The low-noise linear voltage stabilizer provides a stable and reliable 12V direct-current power supply for the detection processing module, and can realize voltage transformation, rectification, filtering (filtering out alternating components), and voltage stabilization (outputting a stable voltage).

[0054] The low-noise linear voltage-stabilized power supply input is isolated by a low-frequency isolation transformer T2 as a power input stage, rectified by diodes D3 and D4 to capacitors C7, C8, C9 and C11 for filtering, and then stabilized by a three-terminal voltage regulator U3 and capacitors C16 and C12 (i.e. the third capacitor and the fourth capacitor) to generate a +12V DC power supply. Another -5V DC power supply is generated by a three-terminal voltage regulator U4 and capacitors C13 and C10. Among them, capacitors C14, C8, C9, C10, C12 and the low-frequency isolation transformer T2 form a low-pass filter network to filter out high-frequency noise. The dashed box 03 is a precision reference unit, which provides a bias input for the detection module.

[0055] The laser detection processing module has the PD laser detection diode D1 in the dashed box 05 as an input port, and is connected to the zero-setting potentiometer W502. When the PD is irradiated by a space laser, the third pin of the operational amplifier U2-A will generate a voltage change corresponding to the laser energy. At the same time, the dashed box 04 generates a 1V bias voltage for the operational amplifier U2-B input after being divided by the precision reference input. The radio frequency operational amplifiers U2-A, U2-B and U1-B (i.e. the first radio frequency operational amplifier, the second radio frequency operational amplifier and the third radio frequency operational amplifier) form a same-phase proportional differential amplifier circuit, which greatly improves the common-mode rejection ratio and performs two-stage amplification on the detection signal by a high multiple. The detection signal is output to the later-stage filter unit 08 by the resistor R3. The resistors R2, R21, R26 and R3 (i.e. the first resistor, the second resistor, the third resistor and the fourth resistor) are also shown in the dashed box 07.

[0056] The U1-A, R3, R4, C5 and C6 in the dashed box 08 form a second-order active filter to filter out high-frequency noise above 800M. Finally, a 50Ω coaxial output is made by the dashed box 09.

[0057] In this embodiment, a low-frequency linear voltage-stabilized dual power supply is used as the power supply input of the detection module, a bias voltage is used as the input end of the proportional amplifier, a radio frequency operational amplifier is used to form a same-phase proportional differential amplifier, and a second-order active low-pass filter is used as the final-stage filter and coupling output.

[0058] The high-speed low-noise laser signal detection device provided by the embodiment of the application has a laser detection bandwidth increased from a maximum of 100MHZ to 500MHZ or even higher, a measurement noise reduced from 10PW / HZ to 0.1PW / HZ or below, improved stability of a long-term power supply machine, and reduced power input noise.

[0059] Although the application is disclosed as above, the application is not limited thereto. Any person skilled in the art can make various modifications and changes without departing from the spirit and scope of the application, and the protection scope of the application should be subject to the range defined by the claims.

[0060] Finally, it is to be understood that the phraseology or terminology such as "including" or "comprising" or "consisting of" used in this specification is open-ended and not intended to preclude that there can be additional items or components other than the ones listed or that the implementations can consist of the ones listed. Also, the phrase "consisting essentially of" is defined to include the additional element or elements and excludes other elements that are not specified. Finally, it is to be understood that the use of the term "or" in referring to a list of items should be understood as indicating an inclusive rather than a exclusive list. That is, unless it is clear from the context, the phrase "X employs A or B" means that X employs A or B or both. Further, unless otherwise indicated herein, the use of the term "or" in the claims should not be understood as having an exclusive or exhaustive meaning.

[0061] The above description of disclosed embodiments provides enabling teaching to a person skilled in the art to implement or use the present application. Numerous modifications to these embodiments will be apparent to those skilled in the art, and general principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Therefore, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. Industrial Applicability

[0062] The high-speed low-noise laser signal detection device provided by the embodiments of the present application can expand the detection bandwidth of the laser signal, reduce the signal-to-noise ratio of high-frequency pulse measurement, and improve the anti-interference characteristics of the power supply.

Claims

1. A high-speed, low-noise laser signal detection device, characterized in that, Includes a low-noise linear regulated power supply and a laser detection and processing module; The low-noise linear regulated power supply includes an isolation unit, a voltage regulation and filtering unit, and a reference unit. The laser detection and processing module includes a laser signal detection input unit, a bias unit, a differential amplification unit, an active filtering unit, and an output interface unit. The output terminal of the voltage stabilizing filter unit is connected to the reference unit and the laser detection and processing module, and is configured to supply power to the reference unit, the differential amplifier unit and the active filter unit; The reference unit is connected to the bias unit and configured to provide a reference voltage to the bias unit, and the bias unit is configured to provide a bias voltage to the differential amplifier unit; The differential amplifier unit includes a multi-stage in-phase differential amplifier circuit, and the active filter unit includes a multi-stage active low-pass filter.

2. The high-speed, low-noise laser signal detection device according to claim 1, characterized in that, The multi-stage non-inverting differential amplifier circuit includes: a first RF operational amplifier, a second RF operational amplifier, and a third RF operational amplifier; The non-inverting input terminal of the first RF operational amplifier is connected to the laser signal detection input unit, and the inverting input terminal is connected to the inverting input terminal of the second RF operational amplifier; The non-inverting input of the second RF operational amplifier is connected to the bias output port of the bias unit; The output terminal of the first RF operational amplifier is connected to the non-inverting input terminal of the third RF operational amplifier, and the output terminal of the second RF operational amplifier is connected to the inverting input terminal of the third RF operational amplifier; The output of the third RF operational amplifier is connected to the active filter unit.

3. The high-speed, low-noise laser signal detection device according to claim 2, characterized in that, The inverting input terminal of the first RF operational amplifier is connected to the output terminal through a first resistor; The inverting input terminal of the second RF operational amplifier is connected to the output terminal through a second resistor; The non-inverting input terminal of the third RF operational amplifier is grounded through a third resistor; The output of the third RF operational amplifier is connected to the active filter unit via a fourth resistor.

4. The high-speed, low-noise laser signal detection device according to claim 2, characterized in that, The multi-order active low-pass filter is a second-order Butterworth active filter.

5. The high-speed, low-noise laser signal detection device according to claim 4, characterized in that, The second-order Butterworth active filter includes an operational amplifier, a fourth resistor, a fifth resistor, a first capacitor, and a second capacitor; The positive input terminal of the operational amplifier is connected to the positive DC output terminal of the voltage regulator and filter unit, and the negative input terminal of the operational amplifier is connected to the negative DC output terminal of the voltage regulator and filter unit. The fourth resistor and the fifth resistor are connected between the output terminal of the multi-stage non-inverting differential amplifier circuit and the non-inverting input terminal of the operational amplifier; One end of the first capacitor is connected between the fourth resistor and the fifth resistor, and the other end is connected to the inverting input terminal of the operational amplifier; One end of the second capacitor is connected between the fifth resistor and the non-inverting input of the operational amplifier, and the other end is grounded.

6. The high-speed, low-noise laser signal detection device according to any one of claims 2-5, characterized in that, The laser signal detection input unit includes a photodiode and a zero-adjustment potentiometer; One end of the zero-adjustment potentiometer is connected to the reference unit, and the other end is connected to the negative terminal of the photodiode; The positive terminal of the photodiode is connected to the non-inverting input terminal of the first RF operational amplifier and grounded through an RC filter circuit; The photodiode is configured to receive the laser signal to be detected.

7. The high-speed, low-noise laser signal detection device according to claim 1, characterized in that, The isolation unit is a linear low-frequency isolation transformer.

8. The high-speed, low-noise laser signal detection device according to claim 1, characterized in that, The voltage stabilizing filter unit includes a full-wave rectifier filter circuit and a voltage stabilizing filter circuit.

9. The high-speed, low-noise laser signal detection device according to claim 8, characterized in that, The voltage stabilizing and filtering circuit includes a three-terminal voltage regulator, a third capacitor, and a fourth capacitor; The input terminal of the three-terminal regulator is connected to the output terminal of the full-wave rectifier filter circuit. The third capacitor and the fourth capacitor are connected in parallel and are both connected between the output terminal of the three-terminal regulator and the ground terminal.

10. The high-speed, low-noise laser signal detection device according to claim 1, characterized in that, The reference unit is a precision voltage reference unit.

11. The high-speed, low-noise laser signal detection device according to claim 1, characterized in that, The reference unit is a precision current reference unit.

12. The high-speed, low-noise laser signal detection device according to claim 1, characterized in that, The multi-stage in-phase differential amplifier circuit has 2, 3, or 4 stages.

13. The high-speed, low-noise laser signal detection device according to claim 1, characterized in that, The multi-order active low-pass filter is second-order, third-order, or fourth-order.

14. The high-speed, low-noise laser signal detection device according to claim 1, characterized in that, The laser detection and processing module also includes a coaxial output unit; The coaxial output unit is connected to the multi-stage active low-pass filter and configured to output the laser signal detection result signal.

Images