CN218865126U - Fusion system based on OTDR - Google Patents

Abstract

The utility model relates to an optical sensing technical field especially relates to a fuse system based on OTDR, fuse system includes the light source module, detection light processing module, signal processing module, beam split module, circulator and sensing optical fiber, the detection light output of light source module and the input coupling of detection light processing module, two at least local oscillator light output ends of light source module and signal processing module's input coupling, circulator and detection light processing module's output coupling, circulator and sensing optical fiber coupling, the circulator still with beam split module's input coupling, two at least output and signal processing module couplings of beam split module, utilize the modularization combinatorial design to constitute and fuse the system, the same device reuse problem has been solved, local oscillator light and the scattered light that corresponds pair the processing in signal processing module, can realize external disturbance, the temperature variation, the distributed measurement of multiple target parameters such as meeting an emergency and decay long distance.

Description

A fusion system based on OTDR

technical field

The utility model relates to the technical field of light sensing, in particular to an OTDR-based fusion system.

Background technique

In the development of fiber optic sensors, distributed sensors represent a special class of fiber optic sensors that can monitor different physical parameters (strain, temperature, vibration, and pressure, etc.) at any point along the fiber. When the number of points to be monitored is large, distributed sensors have obvious advantages over traditional point sensors. The main principle of Optical Time-domain Reflectometer (OTDR) to realize optical fiber monitoring is to inject optical pulses into optical fibers as detection signals. When the optical pulse propagates along the optical fiber, the optical fiber will produce Rayleigh scattering in all directions, and the backscattering part of the Rayleigh scattering in each direction will continuously return the optical pulse from different positions of the optical fiber back to back as the pulsed light travels forward. At the initial incident, when the forwardly transmitted probe light encounters the mechanically fixed joint of the optical fiber or the break of the optical fiber, Fresnel reflection will occur. The back Rayleigh scattering signal and the Fresnel reflection signal pass through the circulator and then enter the electro-optical module. According to the time and power of the received back Rayleigh scattering and Fresnel reflection signal, the loss characteristics and length of the optical fiber can be measured. And information such as the location of the fiber break or the mechanically fixed joint.

Phase-sensitive optical time-domain reflectometry (φ-OTDR) technology, Brillouin optical time domain reflectometry (BOTDR) and coherent optical time domain reflectometry (Coherent optical time domain reflectometry) , COTDR) are three widely used distributed optical fiber sensing technologies; φ-OTDR technology is one of the most sensitive technical means in distributed optical fiber sensing. The signal after the optical fiber is disturbed by the outside is continuously collected and processed by the detector, and the change of the optical path is used to demodulate the phase change, and the disturbance information along the fiber is reconstructed, and then the external disturbance information is reconstructed and identified. In many fields have related applications. BOTDR utilizes the characteristic that the frequency difference between spontaneous Burrillouin scattered light and incident light is sensitive to changes in temperature and strain to realize distributed sensing of temperature and strain. COTDR uses coherent detection technology, has high receiver sensitivity, greatly improves the dynamic range of OTDR, and can monitor ultra-long-distance optical fibers. COTDR combined with EDFA (Erbium Doped Fiber Amplifier, Erbium Doped Fiber Amplifier) online amplification can be applied to multi-span long-span wavelength division multiplexing systems to realize the monitoring of multi-span transmission optical cables.

However, most of the existing distributed optical fiber sensing systems are independent systems that work independently, the reuse rate is low, and the operation is more complicated when performing multi-parameter measurement.

Utility model content

In view of the above defects or improvement needs of the prior art, the utility model provides an OTDR-based fusion system, the purpose of which is to solve the problem that most of the existing distributed optical fiber sensing systems are independent systems that work independently, the reuse rate is low, and multi-parameter When measuring, the operation is more complicated.

In order to achieve the above object, according to one aspect of the utility model, a fusion system based on OTDR is provided, the fusion system includes: a light source module, a detection light processing module, a signal processing module, a light splitting module, a circulator and a sensing fiber, in:

The detection light output end of the light source module is coupled to the input end of the detection light processing module, and is suitable for sending detection light to the detection light processing module;

At least two local oscillator light output ends of the light source module are coupled to the input end of the signal processing module, and are suitable for sending local oscillator light of at least two different wavelengths to the signal processing module;

The circulator is coupled to the output end of the detection light processing module, the circulator is coupled to the sensing fiber, and is adapted to obtain detection light from the detection light processing module and send the detection light to the sensor an optical fiber, and obtain the total scattered light from the sensing optical fiber;

The circulator is also coupled to the input end of the optical splitting module, and is suitable for sending the total scattered light to the optical splitting module;

At least two output terminals of the light splitting module are coupled to the signal processing module, and are adapted to decompose the total scattered light into at least two scattered lights, and send all the scattered light to the signal processing module;

Wherein, the local oscillator light and the corresponding scattered light are paired and processed in the signal processing module to realize the measurement of multiple target parameters.

Further, the signal processing module includes: a data acquisition card, a first coherent receiver and a second coherent receiver, wherein:

The first input end of the first coherent receiver is coupled to the optical splitting module, and the second input end is coupled to the light source module;

The first input end of the second coherent receiver is coupled to the optical splitting module, and the second input end is coupled to the light source module;

The output ends of the first coherent receiver and the second coherent receiver are respectively coupled with the data acquisition card, and are suitable for beating the local oscillator light and scattered light, and the data acquisition card is used for beating the frequency The signal is collected and processed to obtain multiple target parameters.

Further, the light source module includes: a first light source, a first coupler, a second light source, a second coupler and a multiplexer:

The input end of the first coupler is coupled to the output end of the first light source, and the first output end of the first coupler is coupled to the second input end of the first coherent receiver;

The input end of the second coupler is coupled to the output end of the second light source, and the first output end of the second coupler is coupled to the second input end of the second coherent receiver;

The first input end of the multiplexer is coupled to the second output end of the first coupler, the second input end of the multiplexer is coupled to the second output end of the second coupler, and the The output end of the multiplexer is coupled to the input end of the detection light processing module, and is suitable for coupling two paths of detection light into the detection light processing module.

Further, the optical splitting module includes a wave splitter, wherein:

The input end of the wave splitter is coupled to the circulator, the first output end of the wave splitter is coupled to the first input end of the first coherent receiver, and the second output end of the wave splitter Coupled with the first input end of the second coherent receiver, adapted to decompose the total scattered light into the first scattered light and the third scattered light, send the first scattered light to the first coherent receiver, and send the second scattered light three scattered light is sent to the second coherent receiver;

The first coherent receiver is used to beat the first local oscillator light from the first coupler and the first scattered light from the wave splitter, and the second coherent receiver is used to beat the first local oscillator light from the wave splitter. Beating the third local oscillator light of the second coupler and the third scattered light from the wave splitter;

The first local oscillator light is the local oscillator light of φ-OTDR, the first scattered light is the scattered light of φ-OTDR, the third local oscillator light is the local oscillator light of COTDR, and the third scattered light is the scattered light of COTDR, and the fusion system is a fusion system of φ-OTDR and COTDR.

Further, the light source module also includes an electro-optic modulator, and the light splitting module includes a wave splitter and a narrowband filter, wherein:

The input end of the wave splitter is coupled to the circulator, the first output end of the wave splitter is coupled to the input end of the narrowband filter, the second output end of the wave splitter is coupled to the first The first input ends of the two coherent receivers are coupled, and the second output end of the narrowband filter is coupled to the first input end of the first coherent receiver;

The input end of the electro-optic modulator is coupled to the first output end of the first coupler, and the output end of the electro-optic modulator is coupled to the second input end of the first coherent receiver;

The first coherent receiver is used to beat the second local oscillator light from the electro-optic modulator and the second scattered light from the narrowband filter, and the second coherent receiver is used to beat the second local oscillator light from the narrowband filter. Beating the third local oscillator light of the second coupler and the third scattered light from the wave splitter;

The second local oscillator light is local oscillator light of BOTDR, the second scattered light is scattered light of BOTDR, the third local oscillator light is local oscillator light of COTDR, and the third scattered light is scattered light of COTDR In addition, the fusion system is a fusion system of BOTDR and COTDR.

Further, the signal processing module further includes a third coherent receiver, and the light source module further includes a third coupler, wherein:

The input terminal of the third coupler is coupled to the first output terminal of the first coupler, and the first output terminal of the third coupler is coupled to the second input terminal of the third coherent receiver, so The second output end of the third coupler is coupled to the input end of the electro-optic modulator, and the first input end of the third coherent receiver is coupled to the first output end of the narrowband filter;

The third coherent receiver is configured to beat the first local oscillator light from the third coupler and the first scattered light from the narrowband filter;

The first local oscillator light is the local oscillator light of φ-OTDR, the first scattered light is the scattered light of φ-OTDR, and the fusion system is the fusion system of φ-OTDR, BOTDR and COTDR.

Further, the output of the second output port of the wave splitter is the Rayleigh scattered light of the first preset wavelength, the output of the first output port of the narrowband filter is the Rayleigh scattered light of the second preset wavelength, and the narrowband filter The output of the second output terminal is Brillouin scattered light. Further, the light source module includes a first light source, a first coupler, a third coupler, and an electro-optical modulator, and the light splitting module includes a narrowband filter, wherein:

The input end of the first coupler is coupled to the output end of the first light source, the first output end of the first coupler is coupled to the input end of the third coupler, and the first coupler's The second output end is coupled to the input end of the detection light processing module;

The first output end of the third coupler is coupled to the second input end of the first coherent receiver, the second output end of the third coupler is coupled to the input end of the electro-optical modulator, and the an input terminal of the electro-optic modulator is coupled to a second input terminal of the second coherent receiver;

The input end of the narrowband filter is coupled to the circulator, the first output end of the narrowband filter is coupled to the first input end of the first coherent receiver, and the second output end of the narrowband filter coupled to a second input of said first coherent receiver;

The first coherent receiver is used to beat the first local oscillator light from the third coupler and the first scattered light from the narrowband filter, and the second coherent receiver is used to beat the first local oscillator light from the narrowband filter. Beating the second local oscillator light of the electro-optic modulator and the second scattered light of the narrowband filter;

The first local oscillator light is the local oscillator light of φ-OTDR, the first scattered light is the scattered light of φ-OTDR, the second local oscillator light is the local oscillator light of BOTDR, and the second scattered light is the scattered light of BOTDR, and the fusion system is φ-OTDR and BOTDR fusion system.

Further, the detection light processing module includes an acousto-optic modulator and an amplifier, wherein:

The input end of the acousto-optic modulator is coupled to the detection light output end of the light source module, the output end of the acousto-optic modulator is coupled to the input end of the amplifier, and the output end of the amplifier is coupled to the circulator coupling adapted to send the processed probe light to the circulator.

Further, both the first coherent receiver and the second coherent receiver include a polarization graded mixer and a PD detector.

In the utility model, the detection light output end of the light source module is coupled to the input end of the detection light processing module, and at least two local oscillator light output ends of the light source module are coupled to the input end of the signal processing module , the circulator is coupled to the output end of the detection light processing module, the circulator is coupled to the sensing fiber, the circulator is also coupled to the input end of the optical splitting module, and at least the optical splitting module The two output terminals are coupled to the signal processing module, and the fusion system is formed by modular combination design. The local oscillator light and the corresponding scattered light are paired and processed in the signal processing module to realize the measurement of multiple target parameters. Integrating the functions of multiple OTDRs into the fusion system solves the problem of repeated use of the same device, and can realize distributed measurement of multi-objective parameters such as external disturbance, temperature change, strain or long-distance attenuation.

Description of drawings

In order to illustrate the technical solution of the embodiment of the utility model more clearly, the accompanying drawings used in the embodiment of the utility model will be briefly introduced below. Apparently, the drawings described below are only some embodiments of the present utility model, and those skilled in the art can obtain other drawings according to these drawings without creative work.

Fig. 1 is the structural representation of a kind of fusion system based on OTDR that the utility model embodiment provides;

Fig. 2 is a schematic diagram of a φ-OTDR and COTDR fusion system based on an OTDR fusion system provided by the embodiment of the present invention;

Fig. 3 is a kind of BOTDR and COTDR fusion system schematic diagram of the fusion system based on OTDR that the utility model embodiment provides;

Fig. 4 is a schematic diagram of a φ-OTDR, BOTDR and COTDR fusion system based on an OTDR fusion system provided by the embodiment of the present invention;

Fig. 5 is a schematic diagram of a φ-OTDR and BOTDR fusion system of an OTDR-based fusion system provided by an embodiment of the present invention.

Detailed ways

In order to make the purpose, technical solution and advantages of the utility model clearer, the utility model will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model, and are not intended to limit the utility model. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not constitute conflicts with each other.

In the description of the present utility model, the orientation or positional relationship indicated by the terms "inner", "outer", "longitudinal", "transverse", "upper", "lower", "top", "bottom" etc. are based on the attached The orientation or positional relationship shown in the figure is only for the convenience of describing the utility model and does not require the utility model to be constructed and operated in a specific orientation, so it should not be construed as a limitation of the utility model.

In the present invention, unless otherwise clearly specified and limited, a first feature being "on" or "below" a second feature may include direct contact between the first and second features, and may also include the first and second features being in direct contact with each other. The features are not in direct contact but through another feature between them. Moreover, "above", "above" and "above" the first feature on the second feature include that the first feature is directly above and obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature. "Below", "beneath" and "under" the first feature to the second feature include that the first feature is directly below and obliquely below the second feature, or simply means that the first feature has a lower level than the second feature.

Example 1:

Embodiment 1 provides an OTDR-based fusion system. Referring to FIG. 1 , the fusion system includes: a light source module, a detection light processing module, a signal processing module, a light splitting module, a circulator and a sensing fiber.

The detection light output end of the light source module is coupled to the input end of the detection light processing module, and is suitable for sending detection light to the detection light processing module.

At least two local oscillator light output ends of the light source module are coupled to the input end of the signal processing module, and are suitable for sending local oscillator light of at least two different wavelengths to the signal processing module.

The circulator is coupled to the output end of the detection light processing module, the circulator is coupled to the sensing fiber, and is adapted to obtain detection light from the detection light processing module and send the detection light to the sensor optical fiber, and obtain the total scattered light from the sensing optical fiber.

The circulator is also coupled to the input end of the light splitting module, and is suitable for sending the total scattered light to the light splitting module.

At least two output ends of the light splitting module are coupled to the signal processing module, and are suitable for decomposing the total scattered light into at least two paths of scattered light, and sending all the scattered light to the signal processing module.

Wherein, the local oscillator light and the corresponding scattered light are paired and processed in the signal processing module to realize the measurement of multiple target parameters, and the sensing fiber adopts G.652 single-mode fiber.

The essence of the probe light is a light pulse. When the light pulse propagates along the optical fiber, the fiber will produce Rayleigh scattering in all directions, and the backscattering part of the Rayleigh scattering in each direction will dissipate along with the forward transmission of the light pulse. Continuously returning back to the initial incidence of the light pulse from different positions of the fiber, when the forwardly transmitted detection light encounters the mechanically fixed joint of the fiber or the break of the fiber, Fresnel reflection will occur. The total scattered light is the Rayleigh backscattering signal and the Fresnel reflection signal, the Rayleigh backscattering signal and the Fresnel reflection signal enter the light splitting module after passing through the circulator, and the light splitting module performs a process on the total scattered light By splitting the light, the Rayleigh scattered light and Brillouin scattered light of a specific wavelength can be obtained, and the loss characteristics, length, and position of the fiber break or mechanically fixed joint can be measured.

In the utility model, the detection light output end of the light source module is coupled to the input end of the detection light processing module, and at least two local oscillator light output ends of the light source module are coupled to the input end of the signal processing module , the circulator is coupled to the output end of the detection light processing module, the circulator is coupled to the sensing fiber, the circulator is also coupled to the input end of the optical splitting module, and at least the optical splitting module The two output terminals are coupled to the signal processing module, and the fusion system is formed by modular combination design. The local oscillator light and the corresponding scattered light are paired and processed in the signal processing module to realize the measurement of multiple target parameters. Integrating the functions of multiple OTDRs into the fusion system solves the problem of repeated use of the same device, and can realize distributed measurement of multi-objective parameters such as external disturbance, temperature change, strain and long-distance attenuation.

In order to perform beat frequency on multiple local oscillator lights and scattered light, and perform multiple parameter measurements, the signal processing module includes: a data acquisition card, a first coherent receiver and a second coherent receiver, wherein:

The first input end of the first coherent receiver is coupled to the optical splitting module, and the second input end is coupled to the light source module; the first input end of the second coherent receiver is coupled to the optical splitting module, and the second input end is coupled to the optical splitting module. The two input terminals are coupled with the light source module; the output terminals of the first coherent receiver and the second coherent receiver are respectively coupled with the data acquisition card, and are suitable for beating local oscillator light and scattered light, so The above data acquisition card is used to collect and process the beat frequency signal, and then obtain multiple target parameters.

In this embodiment, in order to generate probe light and multiple local oscillator lights, the light source module includes: a first light source, a first coupler, a second light source, a second coupler and a multiplexer.

An input end of the first coupler is coupled to an output end of the first light source, and a first output end of the first coupler is coupled to a second input end of the first coherent receiver.

An input end of the second coupler is coupled to an output end of the second light source, and a first output end of the second coupler is coupled to a second input end of the second coherent receiver.

The first input end of the multiplexer is coupled to the second output end of the first coupler, the second input end of the multiplexer is coupled to the second output end of the second coupler, and the The output end of the multiplexer is coupled to the input end of the detection light processing module, and is suitable for coupling two paths of detection light into the detection light processing module.

In order to form the fusion system of φ-OTDR and COTDR, with reference to FIG. 2, the optical splitter module includes a wave splitter, the input end of the wave splitter is coupled with the circulator, and the first output end of the wave splitter is connected to the first output end of the wave splitter. The first input end of the first coherent receiver is coupled, the second output end of the wave splitter is coupled to the first input end of the second coherent receiver, and is suitable for decomposing the total scattered light into the first scattered light and third scattered light, sending the first scattered light to the first coherent receiver, and sending the third scattered light to the second coherent receiver.

The first coherent receiver is used to beat the first local oscillator light from the first coupler and the first scattered light from the wave splitter, and the second coherent receiver is used to beat the first local oscillator light from the wave splitter. The third local oscillator light of the second coupler and the third scattered light from the wave splitter perform frequency beat.

The first local oscillator light is the local oscillator light of φ-OTDR, the first scattered light is the scattered light of φ-OTDR, the third local oscillator light is the local oscillator light of COTDR, and the third scattered light is the scattered light of COTDR, and the fusion system is a fusion system of φ-OTDR and COTDR.

Wherein, the first local oscillator light reaches the second input end of the first coherent receiver from the first output end of the first coupler, and the first scattered light reaches the second input end of the first coherent receiver from the first output end of the wave splitter. The output goes to a first input of said first coherent receiver.

The third local oscillator light reaches the second input end of the second coherent receiver from the first output end of the second coupler, and the third scattered light passes from the second output end of the wave splitter to the first input of the second coherent receiver.

In order to form a fusion system of BOTDR and COTDR, referring to FIG. 3 , the light source module further includes an electro-optic modulator, and the light splitting module includes a wave splitter and a narrowband filter.

The input end of the wave splitter is coupled to the circulator, the first output end of the wave splitter is coupled to the input end of the narrowband filter, the second output end of the wave splitter is coupled to the first The first input ends of the two coherent receivers are coupled, and the second output end of the narrowband filter is coupled to the first input end of the first coherent receiver.

The input end of the electro-optic modulator is coupled to the first output end of the first coupler, and the output end of the electro-optic modulator is coupled to the second input end of the first coherent receiver.

The first coherent receiver is used to beat the second local oscillator light from the electro-optic modulator and the second scattered light from the narrowband filter, and the second coherent receiver is used to beat the second local oscillator light from the narrowband filter. beat the third local oscillator light from the second coupler and the third scattered light from the wave splitter.

The second local oscillator light is local oscillator light of BOTDR, the second scattered light is scattered light of BOTDR, the third local oscillator light is local oscillator light of COTDR, and the third scattered light is scattered light of COTDR In addition, the fusion system is a fusion system of BOTDR and COTDR.

Wherein, the first local oscillator light reaches the electro-optic modulator from the first output end of the first coupler, and the electro-optic modulator converts the first local oscillator light into a second local oscillator light, and the first local oscillator light Two local oscillator lights arrive at the second input of the first coherent receiver from the electro-optic modulator. The first scattered light reaches the narrowband filter from the first output end of the wave splitter, and the narrowband filter separates the second scattered light from the first scattered light, and the second scattered light passes through the The second output terminal of the narrowband filter reaches the first input terminal of the first coherent receiver.

The third local oscillator light reaches the second input end of the second coherent receiver from the first output end of the second coupler, and the third scattered light passes from the second output end of the wave splitter to the first input of the second coherent receiver.

In order to form a fusion system of φ-OTDR, BOTDR and COTDR, referring to FIG. 4 , the signal processing module further includes a third coherent receiver, and the light source module further includes a third coupler.

The input terminal of the third coupler is coupled to the first output terminal of the first coupler, and the first output terminal of the third coupler is coupled to the second input terminal of the third coherent receiver, so The second output end of the third coupler is coupled to the input end of the electro-optic modulator, and the first input end of the third coherent receiver is coupled to the first output end of the narrowband filter.

The third coherent receiver is used to beat the first local oscillator light from the third coupler and the first scattered light from the narrowband filter.

The first local oscillator light is the local oscillator light of φ-OTDR, the first scattered light is the scattered light of φ-OTDR, and the fusion system is the fusion system of φ-OTDR, BOTDR and COTDR.

Wherein, the first local oscillator light reaches the third coupler from the first output end of the first coupler, and the third coupler splits the first local oscillator light, and a part of the split first The local oscillator light reaches the second input end of the third coherent receiver through the first output end of the third coupler; the first scattered light reaches the narrowband from the first output end of the wave splitter A filter, which reaches the first input end of the third coherent receiver through the first output end of the narrowband filter.

Another part of the first local oscillator light after splitting by the third coupler reaches the electro-optic modulator through the second output end of the third coupler, and the electro-optic modulator converts the first local oscillator light into the first local oscillator light Two local oscillator lights, the second local oscillator light reaches the second input end of the first coherent receiver from the electro-optical modulator; the first scattered light reaches the first output end of the wave splitter a narrowband filter that separates second scattered light from the first scattered light, the second scattered light passing through the second output of the narrowband filter to the first coherent receiver of the first input.

The third local oscillator light reaches the second input end of the second coherent receiver from the first output end of the second coupler, and the third scattered light passes from the second output end of the wave splitter to the first input of the second coherent receiver.

In order to form a fusion system of φ-OTDR and BOTDR, referring to FIG. 5 , the light source module includes a first light source, a first coupler, a third coupler and an electro-optic modulator, and the light splitting module includes a narrowband filter.

The input end of the first coupler is coupled to the output end of the first light source, the first output end of the first coupler is coupled to the input end of the third coupler, and the first coupler's The second output end is coupled to the input end of the detection light processing module.

The first output end of the third coupler is coupled to the second input end of the first coherent receiver, the second output end of the third coupler is coupled to the input end of the electro-optical modulator, and the The input terminal of the electro-optical modulator is coupled to the second input terminal of the second coherent receiver.

The input end of the narrowband filter is coupled to the circulator, the first output end of the narrowband filter is coupled to the first input end of the first coherent receiver, and the second output end of the narrowband filter coupled to the second input of the first coherent receiver.

The first coherent receiver is used to beat the first local oscillator light from the third coupler and the first scattered light from the narrowband filter, and the second coherent receiver is used to beat the first local oscillator light from the narrowband filter. The second local oscillator light of the electro-optic modulator and the second scattered light of the narrow-band filter perform frequency beating.

The first local oscillator light is the local oscillator light of φ-OTDR, the first scattered light is the scattered light of φ-OTDR, the second local oscillator light is the local oscillator light of BOTDR, and the second scattered light is the scattered light of BOTDR, and the fusion system is φ-OTDR and BOTDR fusion system.

Wherein, the first local oscillator light reaches the third coupler from the first output end of the first coupler, and the third coupler splits the first local oscillator light, and a part of the split first The local oscillator light reaches the second input end of the first coherent receiver through the first output end of the third coupler; the first scattered light reaches the second input end through the first output end of the narrowband filter. A first input terminal of a coherent receiver.

Another part of the first local oscillator light after splitting by the third coupler reaches the electro-optic modulator through the second output end of the third coupler, and the electro-optic modulator converts the first local oscillator light into the first local oscillator light Two local oscillator lights, the second local oscillator light reaches the second input end of the second coherent receiver from the electro-optic modulator; the second scattered light reaches the second output end of the narrowband filter to the The first input of the second coherent receiver.

In this embodiment, the detection light processing module includes an acousto-optic modulator and an amplifier, the input end of the acousto-optic modulator is coupled to the detection light output end of the light source module, and the output end of the acousto-optic modulator coupled to the input end of the amplifier, and the output end of the amplifier is coupled to the circulator, and is adapted to send the processed detection light to the circulator. The amplifier is adapted to amplify the probe light in order to return the total scattered light.

In order to realize the measurement of different parameters, the output of the second output port of the wave splitter is the Rayleigh scattered light of the first preset wavelength, and the output of the first output port of the narrowband filter is the Rayleigh scattered light of the second preset wavelength , the output of the second output terminal of the narrowband filter is Brillouin scattered light.

Specifically, the light split from the first output end of the wave splitter includes Rayleigh scattered light with a center wavelength of 1550.12 nm, which is the first scattered light; The Rayleigh scattered light is the third scattered light; the Rayleigh scattered light with a center wavelength of 1550.12nm is transmitted through the first output port of the narrowband filter, which is the first scattered light; the second output port of the narrowband filter What is reflected is Brillouin scattered light with a center wavelength of 1550.2 nm, which is the second scattered light.

The probe light includes the probe light with a center wavelength of 1550.12nm and the probe light with a center wavelength of 1555nm. After the probe light with a center wavelength of 1550.12nm enters the optical fiber, the returned total scattered light includes Rayleigh scattering with a center wavelength of 1550.12nm Light and Brillouin light with a central wavelength of 1550.2nm, but the Brillouin light is very weak, so in the BOTDR system, a narrow-band filter is required to reflect the Brillouin light.

In this embodiment, both the first coherent receiver and the second coherent receiver include a polarization graded mixer and a PD detector, and the coherent receiver is small in size and highly practical.

In this embodiment, the first light source uses a narrow linewidth laser with an output optical power of 12dBm as the light source, the center wavelength is 1550.12nm, and the linewidth is less than 3KHz; the second light source uses a laser with an output optical power of 15dBm. The light source has a center wavelength of 1555nm and a line width of the order of 100KHz.

The light splitting ratio of the first coupler is 90:10, the first output end light splitting ratio of the first coupler is 90%, the second output end light splitting ratio is 10%, and the first output end light splitting ratio of the first coupler is 10%. The output end outputs the first local oscillator light, the first local oscillator light is the local oscillator light used in the φ-OTDR system, and the center wavelength is 1550.12nm.

The light splitting ratio of the second coupler is 50:50, the light splitting ratios of the first output end of the second coupler and the second output end are both 50%, and the first output end of the second coupler outputs the third The local oscillator light, the third local oscillator light is the local oscillator light used in the COTDR system, and the center wavelength is 1555nm.

The light splitting ratio of the third coupler is 30:70, the first output end light splitting ratio of the third coupler is 30%, the second output end light splitting ratio is 70%, the input end of the third coupler and The first output end of the first coupler is coupled to split the first local oscillator light.

The operating frequency of the electro-optic modulator is 9-12 GHz, and the electro-optic modulator is used to convert the first local oscillator light into a second local oscillator light. The second local oscillator light is the local oscillator light used by the BOTDR system, and the center wavelength is 1550.2nm, specifically, the electro-optic modulator includes a radio frequency source and a bias point controller, which will generate two sidebands around the light with a central wavelength of 1550.12nm, and the central wavelength of light near the right band is 1550.2nm, which is the first Two vibrations.

The above descriptions are only preferred embodiments of the present utility model, and are not intended to limit the present utility model. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present utility model shall be included in this utility model. within the scope of protection of utility models.

Claims (10)

1. An OTDR based fusion system, characterized in that said fusion system comprises: light source module, detection light processing module, signal processing module, beam splitting module, circulator and sensing fiber, wherein:

the detection light output end of the light source module is coupled with the input end of the detection light processing module and is suitable for sending detection light to the detection light processing module;

at least two local oscillator light output ends of the light source module are coupled with the input end of the signal processing module and are suitable for sending local oscillator light with at least two different wavelengths to the signal processing module;

the circulator is coupled with the output end of the detection light processing module, and the circulator is coupled with the sensing optical fiber and is suitable for acquiring detection light from the detection light processing module, sending the detection light to the sensing optical fiber and acquiring total scattered light from the sensing optical fiber;

the circulator is also coupled with the input end of the light splitting module and is suitable for sending total scattered light to the light splitting module;

the at least two output ends of the light splitting module are coupled with the signal processing module, and the light splitting module is suitable for splitting total scattered light into at least two paths of scattered light and sending all the scattered light to the signal processing module;

and the local oscillator light and the corresponding scattered light are subjected to pairing processing in the signal processing module, so that the measurement of a plurality of target parameters is realized.

2. The OTDR based fusion system of claim 1, characterized in that said signal processing module comprises: data acquisition card, first coherent receiver and second coherent receiver, wherein:

a first input end of the first coherent receiver is coupled with the light splitting module, and a second input end of the first coherent receiver is coupled with the light source module;

a first input end of the second coherent receiver is coupled with the light splitting module, and a second input end of the second coherent receiver is coupled with the light source module;

the output ends of the first coherent receiver and the second coherent receiver are respectively coupled with the data acquisition card, and the data acquisition card is suitable for performing beat frequency on the local oscillation light and the scattered light, and is used for acquiring and processing the signals after beat frequency so as to acquire a plurality of target parameters.

3. The OTDR based fusion system of claim 2, characterized in that said light source module comprises: the first light source, the first coupler, the second light source, the second coupler and the combiner are as follows:

an input of the first coupler is coupled to an output of the first optical source, and a first output of the first coupler is coupled to a second input of the first coherent receiver;

an input of the second coupler is coupled to an output of the second light source, and a first output of the second coupler is coupled to a second input of the second coherent receiver;

the first input end of the wave combiner is coupled with the second output end of the first coupler, the second input end of the wave combiner is coupled with the second output end of the second coupler, and the output end of the wave combiner is coupled with the input end of the detection light processing module, so that the detection light processing module is suitable for coupling two paths of detection light into the detection light processing module.

4. The OTDR based fusion system of claim 3, characterized in that said splitting module comprises a splitter, wherein:

an input end of the wave separator is coupled with the circulator, a first output end of the wave separator is coupled with a first input end of the first coherent receiver, a second output end of the wave separator is coupled with a first input end of the second coherent receiver, and the wave separator is suitable for decomposing total scattered light into first scattered light and third scattered light, sending the first scattered light to the first coherent receiver, and sending the third scattered light to the second coherent receiver;

the first coherent receiver is configured to perform beat frequency on the first local oscillation light from the first coupler and the first scattered light from the wave splitter, and the second coherent receiver is configured to perform beat frequency on the third local oscillation light from the second coupler and the third scattered light from the wave splitter;

the first local oscillator light is local oscillator light of phi-OTDR, the first scattered light is scattered light of phi-OTDR, the third local oscillator light is local oscillator light of COTDR, the third scattered light is scattered light of COTDR, and the fusion system is a phi-OTDR and COTDR fusion system.

5. The OTDR based fusion system of claim 3, characterized in that said optical source module further comprises an electro-optical modulator, said splitting module comprising a splitter and a narrow-band filter, wherein:

an input end of the wave separator is coupled with the circulator, a first output end of the wave separator is coupled with an input end of the narrow-band filter, a second output end of the wave separator is coupled with a first input end of the second coherent receiver, and a second output end of the narrow-band filter is coupled with a first input end of the first coherent receiver;

an input of the electro-optical modulator is coupled to a first output of the first coupler, and an output of the electro-optical modulator is coupled to a second input of the first coherent receiver;

the first coherent receiver is used for performing beat frequency on the second local oscillation light from the electro-optical modulator and the second scattered light from the narrow-band filter, and the second coherent receiver is used for performing beat frequency on the third local oscillation light from the second coupler and the third scattered light from the wave splitter;

the second local oscillator light is BOTDR local oscillator light, the second scattered light is BOTDR scattered light, the third local oscillator light is COTDR local oscillator light, the third scattered light is COTDR scattered light, and the fusion system is a BOTDR and COTDR fusion system.

6. The OTDR based fusion system of claim 5, wherein said signal processing module further includes a third phase dry receiver, and said optical source module further includes a third coupler, and wherein:

an input terminal of the third coupler is coupled to the first output terminal of the first coupler, a first output terminal of the third coupler is coupled to the second input terminal of the third coherent receiver, a second output terminal of the third coupler is coupled to the input terminal of the electro-optical modulator, and a first input terminal of the third coherent receiver is coupled to the first output terminal of the narrow-band filter;

the third phase dry receiver is used for performing beat frequency on the first local oscillation light from the third coupler and the first scattered light from the narrow-band filter; the first local oscillator light is local oscillator light of phi-OTDR, the first scattered light is scattered light of phi-OTDR, and the fusion system is a phi-OTDR, BOTDR and COTDR fusion system.

7. An OTDR-based fusion system according to claim 6, wherein the rayleigh scattered light of the first predetermined wavelength is output from the second output of the demultiplexer, the rayleigh scattered light of the second predetermined wavelength is output from the first output of the narrow-band filter, and the brillouin scattered light is output from the second output of the narrow-band filter.

8. The OTDR based fusion system of claim 2, wherein said optical source module includes a first optical source, a first coupler, a third coupler, and an electro-optical modulator, and said optical splitting module includes a narrow-band filter, wherein:

an input end of the first coupler is coupled with an output end of the first light source, a first output end of the first coupler is coupled with an input end of the third coupler, and a second output end of the first coupler is coupled with an input end of the detection light processing module;

a first output of the third coupler is coupled to a second input of the first coherent receiver, a second output of the third coupler is coupled to an input of the electro-optical modulator, and an input of the electro-optical modulator is coupled to a second input of the second coherent receiver;

an input of the narrowband filter is coupled to the circulator, a first output of the narrowband filter is coupled to a first input of the first coherent receiver, and a second output of the narrowband filter is coupled to a second input of the first coherent receiver;

the first coherent receiver is used for performing beat frequency on the first local oscillator light from the third coupler and the first scattered light from the narrow-band filter, and the second coherent receiver is used for performing beat frequency on the second local oscillator light from the electro-optical modulator and the second scattered light from the narrow-band filter;

the first local oscillator light is local oscillator light of phi-OTDR, the first scattered light is scattered light of phi-OTDR, the second local oscillator light is local oscillator light of BOTDR, the second scattered light is scattered light of BOTDR, and the fusion system is a phi-OTDR and BOTDR fusion system.

9. The OTDR based fusion system according to any of claims 1-8, wherein said probe light processing module includes an acousto-optic modulator and an amplifier, where:

the input end of the acousto-optic modulator is coupled with the detection light output end of the light source module, the output end of the acousto-optic modulator is coupled with the input end of the amplifier, and the output end of the amplifier is coupled with the circulator, so that the acousto-optic modulator is suitable for sending the processed detection light to the circulator.

10. An OTDR based fusion system according to any of claims 1-8, characterised in that the first coherent receiver and the second coherent receiver each comprise a polarization-division mixer and a PD detector, respectively.

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