CN206804147U - Inexpensive positioning optical fiber vibration sensing device - Google Patents

Abstract

The technical problem to be solved by the utility model is to realize a multi-event positioning distributed optical fiber vibration sensing device with simple structure and low cost. The output end of the laser is connected to the input end of the pulse light modulator, the output end of the pulse light modulator is connected to the input end of the optical amplifier, the output end of the optical amplifier is connected to the input end of the optical isolator, and the output end of the optical isolator is connected to the input end of the optical isolator. One of the input ends of the coupler is connected, the two output ends of the coupler are respectively connected to two sensing fibers, the other input end of the coupler is connected to the input end of the photodetector, and the output end of the photodetector is connected to the data acquisition and processing module connection. The two output terminals of the pulse driver are respectively connected with the pulse light modulator and the data acquisition and processing module. The monitoring of the vibration event is realized through the backscattered light interference in the two sensing fibers, and the positioning of the vibration event is realized through the optical time domain reflection technology. On the premise of ensuring the detection distance and positioning accuracy, the cost of the system is greatly reduced.

Description

Low-cost positioning fiber optic vibration sensing device

technical field

The utility model relates to the field of optical fiber sensing, in particular to a low-cost multi-event positioning distributed optical fiber vibration sensing field.

Background technique

The optical fiber vibration sensor has the characteristics of simple structure, large detection range, high sensitivity, wide response frequency, strong anti-electromagnetic interference ability, strong concealment, and low environmental requirements. It can be used for real-time monitoring of large industrial sites, as well as real-time monitoring, safety protection and alarm processing of some dangerous places. Therefore, it is a very promising and practical subject to study the positioning distributed optical fiber sensing system.

At present, there are mainly two types of fiber optic vibration sensing systems that can achieve positioning: one is the fiber optic vibration sensing system based on the principle of double M-Z interference. The system can realize long-distance detection and locate the location of the vibration event, but the vibration signal location method based on the double M-Z principle can only locate a single event, and cannot simultaneously locate multiple events. The other is a distributed optical fiber vibration sensing system based on the principle of optical time domain reflectometry (OTDR). The system has the characteristics of accurate positioning, simple operation, and long detection distance. However, the system is based on the self-interference effect of the narrow linewidth optical signal in the backscattered light in the optical fiber to realize vibration sensing. The system needs to use ultra-narrow linewidth lasers and Acousto-optic modulator, the cost of the system is very high and can only be applied in high-end places.

Contents of the invention

The technical problem to be solved by the utility model is to realize a multi-event positioning distributed optical fiber vibration sensing device with simple structure and low cost, which greatly reduces the cost of the system under the premise of ensuring the detection distance and positioning accuracy.

The technical problem to be solved in the utility model is achieved through the following technical solutions:

The utility model provides a low-cost positioning optical fiber vibration sensing device, which comprises a laser, a pulse light modulator, a pulse driver, an optical amplifier, an optical isolator, a coupler, a sensing optical fiber, a photoelectric detector, and a data acquisition and processing module.

The laser is a semiconductor laser that emits a continuous optical signal with a central wavelength of 1310nm and a spectral width of 40nm.

The pulse light modulator adopts an electro-optic modulator to modulate the continuous light signal sent by the semiconductor laser into a pulse light signal of 10 ns-200 ns.

The pulse driver is implemented by an XC3S50AN high-speed FPGA chip, and outputs an electric pulse signal with adjustable width for driving the pulse light modulator.

The optical amplifier adopts an erbium-doped optical fiber amplifier to amplify the pulsed optical signal.

The optical isolator adopts a fiber-optic isolator with a center wavelength of 1310nm to prevent backscattered light from returning to the optical amplifier and semiconductor laser and causing damage to the device.

The coupler adopts a fiber coupler with a center wavelength of 1310 nm, and divides the injected optical signal into two outputs.

The sensing fiber adopts G652 ordinary single-mode fiber, and its loss parameters are 0.35dB/km@1310nm and 0.20dB/km@1550nm.

The photodetector adopts PIN type silicon material photodetector, and its detection spectral range is 800-1700nm.

The data acquisition and processing unit is realized by a 100MHz data acquisition card processing computer.

In order to achieve the above purpose, the technical solution adopted by the utility model is: a low-cost multi-event positioning distributed optical fiber vibration sensing device. The continuous optical signal output by the laser is modulated into a pulsed optical signal by a pulsed optical modulator, and then amplified by an optical amplifier and then input to one port of the coupler through an optical isolator. The pulse light signal input into the coupler is divided into two paths of light by the coupler, and injected into two paths of sensing optical fibers respectively. The backscattered optical signals in the two sensing fibers return to the coupler and interfere in the coupler. The backscattered light signal after interference is input into the photodetector through another input port of the coupler and converted into an electrical signal. The electrical signal output by the photoelectric detector is converted into a digital signal by a high-speed AD acquisition card and then input to the processor for processing to obtain the vibration signal and its position information. The pulse driver generates an electrical pulse signal with adjustable width, drives the pulse light modulator to modulate the continuous light signal into a pulse light signal of a certain width, and at the same time outputs a synchronous pulse signal to the AD acquisition card to drive the AD acquisition to perform data acquisition synchronously.

The utility model has the advantages of being able to simultaneously locate multiple vibration events, and has the characteristics of simple structure and low cost.

Description of drawings

Figure 1 is a structural diagram of a low-cost positioning fiber optic vibration sensor.

detailed description

The technical problem to be solved by the utility model is to realize a multi-event positioning distributed optical fiber vibration sensing device with simple structure and low cost, which greatly reduces the cost of the system under the premise of ensuring the detection distance and positioning accuracy.

The low-cost positioning optical fiber vibration sensing device of the utility model is shown in Fig. 1, and the device includes a laser 1, a pulsed light Optical fiber 7, photoelectric detector 8, data acquisition and processing module 9, pulse driver 10. The continuous optical signal output by the laser 1 is modulated into a pulsed optical signal by the pulsed optical modulator 2 , and then amplified by the optical amplifier 3 and then input to one of the input ports of the coupler 5 through the optical isolator 4 . The pulse light signal input into the coupler is divided into two paths by the coupler, and injected into the sensing fiber 6 and the sensing fiber 7 respectively. The backscattered optical signals in the sensing fiber 6 and the sensing fiber 7 return to the coupler 5 and interfere in the coupler 5 . The backscattered light signal after interference is input into the photodetector 8 through another input port of the coupler 5 and converted into an electrical signal. The electrical signal output by the photodetector 8 is input to the data acquisition and processing module 9 for analog-to-digital conversion and processing to obtain the vibration signal and its position information. The pulse driver 10 generates an electrical pulse signal with adjustable width, drives the pulse light modulator 2 to modulate the continuous light signal into a pulse light signal of a certain width, and simultaneously outputs a synchronous pulse signal to the data acquisition and processing module, and drives the data acquisition and processing module to perform data synchronously. collection and processing.

The utility model has been exemplarily described above in conjunction with the accompanying drawings. Obviously, the specific implementation of the utility model is not limited by the above-mentioned methods, as long as various insubstantial improvements are made by adopting the method concept and technical solutions of the utility model, or Directly applying the ideas and technical solutions of the utility model to other occasions without improvement is within the protection scope of the utility model.

Claims (3)

1. inexpensive positioning optical fiber vibration sensing device, it is characterised in that：

The output end of laser is connected with the input of pulse optical modulator, the output end of pulse optical modulator and image intensifer Input connects, and the input of the output end of image intensifer and optoisolator connects, the output end of optoisolator and coupler One of input connection, two output ends of coupler connect two-way sensor fibre, another input of coupler respectively It is connected with the input of photodetector, the output end of photodetector is connected with digital sampling and processing；Pulse driver Two output ends be connected respectively with pulse optical modulator and data acquisition processing module.

2. inexpensive positioning optical fiber vibration sensing device according to claim 1, it is characterised in that：

Described coupler uses power-division ratios as 1:1 fiber coupler；One of input of coupler and light every Connected from device, another input of coupler is connected with photodetector；Two output ends of coupler connect two-way respectively Sensor fibre.

3. inexpensive positioning optical fiber vibration sensing device according to claim 1, it is characterised in that：

Described pulse driver is realized using high speed fpga chip, broad-adjustable electric impulse signal is exported, for driving arteries and veins Wash modulator, while output sync pulse signal off；The output of pulse signal interface of pulse driver connects with pulse optical modulator Connect, the synchronizing signal output interface of pulse driver is connected with digital sampling and processing.