CN206311139U - A kind of BOTDR measuring systems based on near-infrared single photon detector - Google Patents

Abstract

The utility model is related to a kind of BOTDR measuring systems based on near-infrared single photon detector,Including system core control module,The system core control module includes computer module and drives nucleus module,The system core control module side is electrically connected with pulse laser emission module,The pulse laser emission module includes lasing light emitter generation module,Isolator module,Acousto-optic modulation module and Erbium-doped fiber amplifier module,And be electrically connected with successively,Acousto-optic modulation module side is electrically connected with AOM drive modules,By the frequency and pulsewidth that adjust laser pulse,Realize that measurement fiber distance is corresponding with the pulse period,It is set to meet simultaneously near,In,The demand of remote fiber linear measure longimetry,In addition,Realize human-computer interaction function,And the parameters of the adjustment system that can suit measures to local conditions,The repetition rate of such as modulating light pulse,Modulation pulsewidth,Scan period of F P etc.,Whole system is set to realize artificial intelligence functionalization,Modernization.

Description

A BOTDR Measurement System Based on Near Infrared Single Photon Detector

technical field

The utility model relates to a BOTDR measurement system based on a near-infrared single-photon detector, which belongs to the field of optical fiber distributed sensing and weak infrared photoelectric detection.

Background technique

Distributed optical fiber sensing, which uses the backscattering phenomenon generated by the propagation of laser light in optical fibers, has broad application prospects in many defense and civilian fields such as communications, remote sensing, aerospace, and military reconnaissance. Distributed sensing methods can be divided into three types: Large categories, distributed sensing based on Rayleigh scattering, distributed sensing based on Brillouin scattering, and sensing based on Raman scattering, to meet the application requirements of different aspects and different measurement accuracy ranges, among which Brillouin scattering based The distributed optical fiber sensing method is that when the optical signal enters the optical fiber, there will be tiny vibrations in the molecules of the optical fiber material, which will lead to changes in the internal structure of the optical fiber, making the refractive index a periodic distribution, and at the same time causing a spontaneous The sound field, so under the action of the sound field, the incident light wave propagating in the optical fiber will produce an inelastic scattering, which is called Brillouin scattering. The distributed sensing technology using this phenomenon is called the distributed sensing technology based on Brillouin scattering. Usually, when the temperature or stress distributed along the optical fiber changes, it will affect the frequency of the Brillouin scattering signal in the optical fiber. In addition, it will also affect the intensity of Brillouin scattered light. In the distributed optical fiber sensor based on Brillouin scattering, a pulse-modulated optical signal is input at the incident end of the optical fiber , when the optical signal propagates in the optical fiber, it will produce backward Rayleigh scattering, Brillouin scattering, and Raman scattering signals (because the Raman signal is weak in this system, it is ignored), and then detected at the incident end along the The Rayleigh scattered light of the fiber length distribution, the intensity information of the Brillouin scattered light and the Brillouin relative frequency shift information are used to realize the simultaneous measurement of the temperature and strain of the fiber, because the Brillouin scattering has high spatial resolution and long sensing distance , high measurement accuracy and other advantages, it shows very attractive application prospects in the safety monitoring and fault early warning and evaluation of large-scale infrastructure facilities such as bridges, tunnels, dams, power communication networks, oil and gas pipelines, etc.

However, due to the very weak light intensity of Brillouin scattered light, it is difficult to detect, which makes BOTDR have great limitations, such as its short measurable distance and low resolution. In order to improve its measurement range, many scientists began to The measurement scheme using single-photon detectors is adopted, but the current single-photon detectors can basically only work at the same frequency, and the current BOTDR system has the following characteristics. If the measurement accuracy is improved, the measurement distance will be shortened. On the contrary If you want to increase the measurement distance, you must reduce the accuracy as a price; this completely limits the performance of the entire system. How to take measures to break through this limitation and further improve the BOTDR measurement distance, resolution and other parameters has become a major problem. Therefore, , needs further improvement.

Utility model content

The technical problem to be solved by the utility model overcomes the existing defects, and provides a BOTDR measurement system based on a near-infrared single photon detector. The measurement system uses a combination of a single photon detector and an F-P scanning system, and uses optical pulse signals F-P scan interference drive signal and SPD trigger signal, the solution of synchronous execution of these three signals, by adjusting the frequency and pulse width of the laser pulse, realizes the correspondence between the measurement fiber distance and the pulse period, so that it can meet the near, medium and long-distance fiber length at the same time In addition to the measurement requirements, the human-computer interaction function is realized, and various parameters of the system can be adjusted according to local conditions, such as the repetition frequency of the modulated light pulse, the modulated pulse width, the scan cycle of F-P, etc., so that the entire system can be realized manually. Intelligent functionalization, modernization, can effectively solve the problems in the background technology.

In order to solve the above technical problems, the utility model provides the following technical solutions:

A BOTDR measurement system based on a near-infrared single photon detector, including a system core control module, the system core control module includes a computer module and a drive core module, one side of the system core control module is electrically connected to a pulsed laser emission module, The pulsed laser emission module includes a laser source generation module, an isolator module, an acousto-optic modulation module and an erbium-doped fiber amplification module, which are electrically connected in sequence. One side of the acousto-optic modulation module is electrically connected to the AOM drive module. The other side of the core control module of the system is electrically connected to the detection module. The detection module includes a single photon detector module, an F-P voltage drive module and an F-P scanning interferometer module, and is electrically connected in sequence. The erbium-doped fiber amplification module is connected to the The F-P scanning interferometer module is electrically connected to the circulator module, and one side of the circulator module is electrically connected to the sensing light module.

As a preferred technical solution of the present invention, the drive core module is electrically connected to the AOM drive module.

As a preferred technical solution of the present invention, the computer module is electrically connected to the single photon detector module.

As a preferred technical solution of the present invention, the driving core module is electrically connected to the single photon detector module and the F-P voltage driving module respectively.

As a preferred technical solution of the present invention, one side of the circulator module is electrically connected to the sensing light module.

Beneficial effects of the utility model: the measurement system combines the single photon detector with the F-P scanning system, and adopts the optical pulse signal, the F-P scanning interference drive signal and the SPD trigger signal. frequency and pulse width, to realize the correspondence between the measured fiber distance and the pulse period, so that it can meet the needs of near, medium and long-distance fiber length measurement at the same time. Item parameters, such as the repetition frequency of modulated light pulses, modulated pulse width, F-P scan period, etc., enable the entire system to realize the functionalization and modernization of artificial intelligence, making it have a great application prospect in the current field of optical fiber communication.

Description of drawings

The accompanying drawings are used to provide a further understanding of the utility model, and constitute a part of the description, and are used to explain the utility model together with the embodiments of the utility model, and do not constitute a limitation to the utility model.

Fig. 1 is a general diagram of a BOTDR measurement system module based on a near-infrared single photon detector of the present invention.

Labels in the figure: 1. System core control module; 2. Computer module; 3. Drive core module; 4. Pulse laser emission module; 5. Laser source generation module; 6. Isolator module; 7. Acousto-optic modulation module; 8 , Erbium-doped fiber amplifier module; 9, AOM drive module; 10, detection module; 11, single photon detector module; 12, F-P voltage drive module; 13, F-P scanning interferometer module; 14, circulator module; 15, transmission Sensitive light module.

detailed description

The preferred embodiments of the present utility model are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described here are only used to illustrate and explain the present utility model, and are not intended to limit the present utility model.

As shown in Figure 1, a BOTDR measurement system based on a near-infrared single photon detector includes a system core control module 1, the system core control module 1 includes a computer module 2 and a drive core module 3, and the power supply on one side of the system core control module 1 Connect the pulsed laser emitting module 4, the pulsed laser emitting module 4 includes a laser source generating module 5, an isolator module 6, an acousto-optic modulation module 7 and an erbium-doped fiber amplifier module 8, and are electrically connected in turn, the acousto-optic modulation module 7- One side is electrically connected to the AOM drive module 9, and the other side of the system core control module 1 is electrically connected to the detection module 10. The detection module 10 includes a single photon detector module 11, an F-P voltage drive module 12 and an F-P scanning interferometer module 13, and sequentially Electrically connected, the erbium-doped fiber amplifier module 8 and the F-P scanning interferometer module 13 are both electrically connected to the circulator module 14 .

The driving core module 3 is electrically connected with the AOM driving module 9, modulated by the AOM to turn it into pulsed light, the computer module 2 is electrically connected with the single photon detector module 11, and the artificial intelligence function is realized through the computer module 2, and the modern driving The core module 3 is electrically connected to the single photon detector module 11 and the F-P voltage driving module 12 respectively, and one side of the circulator module 14 is electrically connected to the sensing light module 15 .

Specifically, first use the core driver module to generate two electrical signals, and by controlling the frequency and pulse width of the laser pulse, realize the correspondence between the measurement fiber distance and the pulse period, and then adjust the system delay to achieve simultaneous Single Photon Detector (SPD) triggering The signal is synchronized with the laser pulse signal; then according to the cumulative measurement time of the detector and the required system resolution, the corresponding F-P scanning voltage drive signal is generated, so that the spatial resolution, measurement time and measurement range of the system can be adjusted according to the needs. system to achieve optimal performance.

The basic process of the BOTDR system: First, set the parameters of the core control module according to the measurement requirements, including laser pulse frequency, pulse width, F-P scan drive voltage range, scan time and other parameters, especially to adjust the delay of the core drive module At the same time, the SPD trigger signal is aligned with the return optical signal; then the 1550nm laser source is started to generate continuous laser light, and after passing through the isolator, it is modulated by AOM to make it into pulsed light, and then the modulated laser light can be sent to EDFA for amplification (depending on the situation Depending on the situation, it is mostly used for long-distance detection), the amplified pulsed laser is coupled into the sensing fiber after passing through the circulator; the backscattered light at a specific point enters the F-P scanning interferometer through the other end of the circulator, so that the backscattering The spectrum of the light is separated; then the light emitted by the F-P cavity is detected by the SPD, and the avalanche signal generated by it is processed by corresponding amplification, integer, modulus, etc., and then sent to the core control module through the serial bus for storage.

The above is a preferred embodiment of the utility model, and those skilled in the art of the utility model can also change and modify the above-mentioned embodiment. Therefore, the utility model is not limited to the above-mentioned specific embodiment. Anyone skilled in the art Any obvious improvement, replacement or modification made on the basis of the present utility model belongs to the protection scope of the present utility model.

Claims (5)

1. a kind of BOTDR measuring systems based on near-infrared single photon detector, including system core control module（1）, it is special Levy and be, the system core control module（1）Including computer module（2）With driving nucleus module（3）, the system core Control module（1）Side is electrically connected with pulse laser emission module（4）, the pulse laser emission module（4）Including lasing light emitter Generation module（5）, isolator module（6）, acousto-optic modulation module（7）With Erbium-doped fiber amplifier module（8）, and electrically connect successively Connect, the acousto-optic modulation module（7）Side is electrically connected with AOM drive modules（9）, the system core control module（1）It is another Side is electrically connected with detecting module（10）, the detecting module（10）Including single photon detector module（11）, F-P voltages drive mould Block（12）With F-P scanning interferometer modules（13）, and be electrically connected with successively, the Erbium-doped fiber amplifier module（8）With the F-P Scanning interferometer module（13）It is electrically connected with circulator module（14）.

2. a kind of BOTDR measuring systems based on near-infrared single photon detector according to claim 1, it is characterised in that： The driving nucleus module（3）With AOM drive modules（9）It is electrically connected with.

3. a kind of BOTDR measuring systems based on near-infrared single photon detector according to claim 1, it is characterised in that： The computer module（2）With the single photon detector module（11）It is electrically connected with.

4. a kind of BOTDR measuring systems based on near-infrared single photon detector according to claim 1, it is characterised in that： The driving nucleus module（3）Respectively with the single photon detector module（11）, F-P voltage drive modules（12）Electrically connect Connect.

5. a kind of BOTDR measuring systems based on near-infrared single photon detector according to claim 1, it is characterised in that： The circulator module（14）Side is electrically connected with sense light wire module（15）.