A multi-channel erbium-doped fiber ultrasonic detection system

Abstract

The application provides a multi-channel erbium-doped optical fiber ultrasonic detection system and relates to the field of erbium-doped optical fiber ultrasonic detection, and comprises an optical amplifier, a polarizer, a first wavelength division multiplexer, n polarization controllers, n circulators, n F-P ultrasonic sensors, a second wavelength division multiplexer, a coupling unit and a data processing unit. The polarizer, the first wavelength division multiplexer, the polarization controller, the circulator and the F-P ultrasonic sensor are added in the ring erbium-doped optical fiber laser, the polarization hole burning effect is utilized, and the n F-P ultrasonic sensors respectively excite corresponding laser wavelengths. The F-P ultrasonic sensor is used as a multi-wavelength filter, the polarization hole burning effect is utilized to realize the vibration of multiple wavelengths, each wavelength can be used as a channel to perform ultrasonic sensing, the cross talk between the n channels can be eliminated, and the multi-wavelength laser vibration is realized, and the response characteristics of the F-P are utilized to realize the multi-channel ultrasonic detection.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of erbium-doped fiber ultrasonic detection, and particularly relates to a multi-channel erbium-doped fiber ultrasonic detection system. BACKGROUND

[0002] Current ultrasonic sensors / systems can be mainly divided into FBG (Fiber Bragg Grating) and fiber F-P (Fabry-Perot) ultrasonic sensors according to different sensing probes.

[0003] The fiber F-P ultrasonic sensor has the advantages of high acoustic pressure sensitivity, small size, anti-electromagnetic interference, long-distance measurement, and easy arraying. The research on the fiber F-P ultrasonic sensor at home and abroad mainly focuses on improving the sensitivity of ultrasonic detection. For the F-P ultrasonic sensor based on the optical reflection diaphragm closed cavity, the general demodulation method is to adjust the wavelength of the narrow-band light source to the maximum slope of the F-P reflection spectrum. However, since the wavelength of the narrow-band light source is fixed, the fiber F-P ultrasonic sensor is easily affected by the external air pressure and temperature, etc., resulting in the drift of the reflection spectrum. Thus, the wavelength of the narrow-band light source is not at the maximum slope, which will lead to the decrease of the sensitivity or the failure of demodulation.

[0004] In order to solve the above problems, researchers use a three-wavelength demodulation method, that is, the single-wavelength narrow-band light source is replaced by three narrow-band light sources with different wavelengths, so that the working point can be at a relatively good slope regardless of the drift of the wavelength. However, this will lead to a fold increase in cost.

[0005] Some researchers add multiple FBGs in a ring erbium-doped fiber laser. The FBG acts as a filter for exciting multiple wavelengths and as a sensitive element for ultrasonic detection, so that the laser can always work at the center wavelength of the FBG. This technology can realize networking of multiple FBG probes, but due to the structural limitations of the FBG, the response sensitivity is very low, and the response ultrasonic frequency is also limited, about 2MHz.

[0006] The F-P ultrasonic sensor can achieve high-sensitivity detection of different frequency ultrasonic waves according to the selection of different diaphragm materials, thicknesses and sizes. However, it is currently difficult to put multiple F-P ultrasonic sensors into an erbium-doped fiber ring laser. Since the reflection spectrum of the F-P ultrasonic sensor covers the full spectrum, the superposition of two F-P reflection spectra will lead to a messy spectrum. The erbium-doped fiber has a broadening gain characteristic, and there is a problem of mode competition, so only one laser will be output. Therefore, it is currently difficult to realize that multiple F-P ultrasonic sensors can work in a laser link at the same time, which greatly reduces the use scenarios of the F-P ultrasonic sensor. SUMMARY

[0007] The application aims to provide a multi-channel erbium-doped fiber ultrasonic detection system, which can realize multi-channel ultrasonic detection and avoid mode competition.

[0008] To achieve the above-mentioned purpose, the application provides the following solutions.

[0009] A multi-channel erbium-doped fiber ultrasonic detection system is used for detecting ultrasonic signals, and comprises:

[0010] An optical amplifier is used for generating a multi-wavelength laser signal with stable energy.

[0011] A polarizer is connected with the optical amplifier and used for obtaining a polarized light signal according to the multi-wavelength laser signal.

[0012] A first wavelength division multiplexer is connected with the polarizer and used for dividing the polarized light signal into n beams according to different wavelengths to obtain n beams of branch light signals; n≥2.

[0013] n detection channels, for any detection channel, each detection channel comprises:

[0014] A polarization controller is connected with the first wavelength division multiplexer and used for regulating the polarization state of a branch light signal output from the first wavelength division multiplexer.

[0015] A circulator is connected with the polarization controller and used for isolating and transmitting the branch light signal.

[0016] An F-P ultrasonic sensor is connected with the circulator and used for filtering the branch light signal to obtain a filtered light signal, and performing acousto-optic modulation on the filtered light signal under the action of a to-be-detected ultrasonic signal to obtain a modulated light signal and return the modulated light signal to the circulator; the cavity lengths of the F-P ultrasonic sensors in the detection channels are different.

[0017] A second wavelength division multiplexer is connected with the circulator in each detection channel and used for combining the modulated light signals to obtain a combined light signal.

[0018] A coupling unit is connected with the second wavelength division multiplexer and the optical amplifier and used for dividing the combined light signal into a first proportion light signal and a second proportion light signal according to the energy proportion; the first proportion light signal is transmitted to the optical amplifier.

[0019] A data processing unit is connected with the coupling unit and used for obtaining a detection result of the to-be-detected ultrasonic signal according to the second proportion light signal.

[0020] Optionally, the optical amplifier comprises:

[0021] a pump source, configured to generate a light source signal;

[0022] an erbium-doped fiber, connected with the pump source, configured to obtain the incident light signal according to the light source signal;

[0023] a third wavelength division multiplexer, arranged between the pump source and the erbium-doped fiber, and connected with the coupling unit, configured to couple the first proportion light signal and the light source signal, and transmit them to the erbium-doped fiber to obtain the multi-wavelength laser signal.

[0024] Optionally, the data processing unit comprises:

[0025] a coupling module, connected with the coupling unit, configured to divide the second proportion light signal into a third proportion light signal and a fourth proportion light signal according to energy proportion;

[0026] a spectrometer, connected with the coupling module, configured to obtain a spectrum diagram under the action of the to-be-measured ultrasonic signal according to the third proportion light signal;

[0027] a processing module, connected with the coupling module, configured to process the fourth proportion light signal to obtain a detection result of the to-be-measured ultrasonic signal.

[0028] Optionally, the processing module comprises:

[0029] a photoelectric conversion sub-module, connected with the coupling module, configured to obtain an electrical signal according to the third proportion light signal;

[0030] a data acquisition sub-module, connected with the photoelectric conversion sub-module, configured to obtain data information according to the electrical signal;

[0031] a data processing sub-module, connected with the data acquisition sub-module, configured to process the data information to obtain the detection result of the to-be-measured ultrasonic signal.

[0032] Optionally, the coupling unit is a 9:1 coupler, and the combined light signal is divided according to an energy proportion of 9:1; the energy proportion of the first proportion light signal is 9, and the energy proportion of the second proportion light signal is 1.

[0033] Optionally, the coupling module is a 5:5 coupler, and the combined light signal is divided according to an energy proportion of 5:5; the energy proportion of the third proportion light signal is 5, and the energy proportion of the fourth proportion light signal is 5.

[0034] Optionally, the pump source is a 980nm laser.

[0035] According to the specific embodiments of the application, the following technical effects are disclosed:

[0036] The multi-channel erbium-doped fiber ultrasonic detection system provided by the application, the optical amplifier generates a multi-wavelength laser signal with stable energy, the polarizer obtains a polarized light signal according to the multi-wavelength laser signal, the first wavelength division multiplexer divides the polarized light signal into n beams according to different wavelengths, obtaining n beams of branch light signals, each beam of branch light signal corresponds to a detection channel, and each detection channel includes a polarization controller and a circulator, each circulator is connected with an F-P ultrasonic sensor, the polarization controller controls the polarization state of the branch light signal, then the branch light signal is isolated and transmitted by the circulator, and is filtered at the F-P ultrasonic sensor, and under the action of the to-be-detected ultrasonic signal, acousto-optic modulation occurs, obtaining a modulated light signal, the n beams of modulated light signals are transmitted to the second wavelength division multiplexer and combined into one, obtaining a combined light signal, the coupling unit divides the combined light signal into a first proportion light signal and a second proportion light signal according to the energy proportion, the first proportion light signal is transmitted to the optical amplifier, and the data processing unit obtains the detection result of the to-be-detected ultrasonic signal according to the second proportion light signal; multi-channel ultrasonic detection is realized, and the mode competition problem is solved. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0038] Figure 1 It is a module structure diagram of the multi-channel erbium-doped fiber ultrasonic detection system of the present application.

[0039] Figure 2 It is a module structure diagram of the embodiment of the multi-channel erbium-doped fiber ultrasonic detection system of the present application.

[0040] Figure 3 It is a double-channel spectrum diagram example.

[0041] Figure 4 It is an ultrasonic detection result example diagram of channel 1 in the double-channel.

[0042] Figure 5 It is a side view of the F-P ultrasonic sensor.

[0043] Figure 6 It is a circular silver film diagram of the F-P sensor.

[0044] Figure 7 It is a normal signal output diagram.

[0045] Figure 8 The schematic diagram for the distorted signal output.

[0046] The arc-shaped dotted line represents the ultrasonic signal.

[0047] Symbol explanation:

[0048] Optical amplifier 1, pump source 11, erbium-doped optical fiber 12, third wavelength division multiplexer 13, polarizer 2, first wavelength division multiplexer 3, polarization controller 4, circulator 5, F-P ultrasonic sensor 6, second wavelength division multiplexer 7, coupling unit 8, data processing unit 9, coupling module 91, optical spectrometer 92, processing module 93, photoelectric conversion sub-module 931, data acquisition sub-module 932, and data processing sub-module 933. DETAILED DESCRIPTION

[0049] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0050] The purpose of the present application is to provide a multi-channel erbium-doped optical fiber ultrasonic detection system, which can realize multi-channel ultrasonic detection and solve the mode competition problem by using an F-P ultrasonic sensor as an erbium-doped optical fiber multi-wavelength filter.

[0051] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0052] As shown in Figure 1 The multi-channel erbium-doped optical fiber ultrasonic detection system of the present application comprises an optical amplifier 1, a polarizer 2, a first wavelength division multiplexer 3, a polarization controller 4, a circulator 5, an F-P ultrasonic sensor 6, a second wavelength division multiplexer 7, a coupling unit 8, and a data processing unit 9.

[0053] Specifically, the optical amplifier 1 is used to generate a multi-wavelength laser signal with stable energy.

[0054] The polarizer 2 is connected with the optical amplifier 1. The polarizer 2 is used to obtain a polarized light signal according to the multi-wavelength laser signal.

[0055] The first wavelength division multiplexer 3 is connected with the polarizer 2. The first wavelength division multiplexer 3 is used to divide the polarized light signal into n beams to obtain n beams of branch light signals; n≥2.

[0056] There are n detection channels. For any detection channel, each detection channel includes: a polarization controller 4, a circulator 5, and an FP ultrasonic sensor 6.

[0057] The polarization controller 4 is connected to the first wavelength division multiplexer 3. The polarization controller 4 is used to regulate the polarization state of a split optical signal output from the first wavelength division multiplexer 3.

[0058] The circulator 5 is connected to the polarization controller 4. The circulator 5 is used for isolated transmission of the split optical signals.

[0059] The FP ultrasonic sensor 6 is connected to the circulator 5. The FP ultrasonic sensor 6 is used to filter the split optical signal to obtain a filtered optical signal, and under the action of the ultrasonic signal to be measured, to perform acousto-optic modulation on the filtered optical signal to obtain a modulated optical signal, which is then transmitted back to the circulator 5. The cavity lengths of the FP ultrasonic sensors 6 in each detection channel are different.

[0060] The second wavelength division multiplexer 7 is connected to the circulator 5 in each detection channel. The second wavelength division multiplexer 7 is used to combine the modulated optical signals into one channel to obtain a combined optical signal.

[0061] The coupling unit 8 is connected to the second wavelength division multiplexer 7 and the optical amplifier 1. The coupling unit 8 is used to divide the synthesized optical signal into a first-ratio optical signal and a second-ratio optical signal according to the energy ratio. The first-ratio optical signal is transmitted to the optical amplifier 1.

[0062] The data processing unit 9 is connected to the coupling unit 8. The data processing unit 9 is used to obtain the detection result of the ultrasonic signal under test based on the second proportion optical signal.

[0063] Preferably, the coupling unit 8 is a 9:1 coupler, and the synthesized optical signal is divided according to a 9:1 energy ratio. The first ratio optical signal has an energy ratio of 9, and the second ratio optical signal has an energy ratio of 1.

[0064] Furthermore, such as Figure 2 As shown, the optical amplifier 1 includes: a pump source 11, an erbium-doped fiber 12, and a third wavelength division multiplexer 13.

[0065] The pump source 11 is used to generate a light source signal.

[0066] Preferably, the pump source is a 980nm laser. The multi-channel erbium-doped fiber ultrasonic detection system provided by the application can select a 980nm laser as the seed light source of the whole system, thereby exciting multi-wavelength laser signals by using an erbium-doped fiber as a gain medium, and realizing multi-channel ultrasonic detection. Compared with the existing three-wavelength demodulation system, the structure is relatively simple, and the cost of the light source can be effectively saved.

[0067] The erbium-doped fiber 12 is connected with the pump source 11. The erbium-doped fiber 12 is used to obtain the multi-wavelength laser signal according to the light source signal.

[0068] The third wavelength division multiplexer 13 is arranged between the pump source 11 and the erbium-doped fiber 12. The third wavelength division multiplexer 13 is connected with the coupling unit 8. The third wavelength division multiplexer 13 is used to couple the first proportion optical signal and the light source signal, and transmit them to the erbium-doped fiber 12 to obtain the multi-wavelength laser signal.

[0069] The multi-channel erbium-doped fiber ultrasonic detection system provided by the application can effectively solve the problem of working point drift. Since the application uses an erbium-doped fiber 12 as a gain medium, uses multiple F-P ultrasonic sensors 6 as filters, introduces polarization hole burning effect, and uses a first wavelength division multiplexer to distinguish the modulated light signals reflected back to the ring cavity by the n F-P ultrasonic sensors 6 in terms of wavelength and polarization, n independent modulated light signals are realized. The n modulated light signals correspond to the n F-P ultrasonic sensors respectively, and are all excited at the maximum of the F-P reflection spectrum. Therefore, when the reflection spectrum of the n F-P ultrasonic sensors 6 is affected by external parameters and drifts, the excitation can always be excited at the maximum of the reflection spectrum, so the problem of working point drift can be effectively solved. As shown in Figure 7 、 Figure 8 , Figure 7 is a normal signal output schematic diagram, Figure 8 is a distorted signal output schematic diagram.

[0070] In addition, as shown in Figure 2 , the data processing unit 9 comprises a coupling module 91, a spectrometer 92 and a processing module 93.

[0071] The coupling module 91 is connected with the coupling unit 8. The coupling module 91 is used to divide the second proportion optical signal into a third proportion optical signal and a fourth proportion optical signal according to the energy proportion.

[0072] The spectrometer 92 is connected with the coupling module 91. The spectrometer 92 is used to obtain a spectrum graph under the action of the to-be-detected ultrasonic signal according to the third proportion optical signal.

[0073] The processing module 93 is connected with the coupling module 91. The processing module 93 is used for processing the fourth proportion light signal to obtain the detection result of the to-be-detected ultrasonic signal.

[0074] Preferably, the coupling module 91 is a 5:5 coupler, and the synthetic light signal is divided according to the energy proportion of 5:5. The third proportion light signal energy proportion is 5, and the fourth proportion light signal energy proportion is 5.

[0075] Specifically, by respectively adjusting the polarization controller 4 in each detection channel until a stable multi-wavelength appears in the optical spectrum diagram under the action of the to-be-detected ultrasonic signal. After the stable multi-wavelength appears in the optical spectrum diagram, the F-P ultrasonic sensor 6 in each detection channel is adjusted respectively to select a wavelength range for filtering, so that there is only one modulated light signal passing through the wavelength interval. The processing module 93 is used for processing to realize the ultrasonic detection of the channel corresponding to the wavelength modulated light signal.

[0076] Taking a double-channel as an example, as shown in Figure 3 , Figure 4 , Figure 3 is the optical spectrum diagram after the stable multi-wavelength appears, and Figure 4 is the ultrasonic detection result of channel 1 after the filtering is completed.

[0077] Optionally, when the polarization controller 4 and the F-P ultrasonic sensor 6 are adjusted, manual operation can be referred to the optical spectrum diagram.

[0078] In addition, the processing module 93 can also be connected with the optical spectrometer 92, the polarization controller 4 and the F-P ultrasonic sensor 6 in each detection channel respectively. The processing module 93 adjusts and controls the operation of the polarization controller 4 and the F-P ultrasonic sensor 6 according to the optical spectrum diagram, and obtains the detection result of the to-be-detected ultrasonic signal according to the fourth proportion light signal after the adjustment and control are completed.

[0079] As shown in Figure 2 , the processing module 93 comprises an optical-electric conversion sub-module 931, a data acquisition sub-module 932 and a data processing sub-module 933.

[0080] The optical-electric conversion sub-module 931 is connected with the coupling module 91. The optical-electric conversion sub-module 931 is used for obtaining an electric signal according to the third proportion light signal.

[0081] The data acquisition sub-module 932 is connected with the optical-electric conversion sub-module 931. The data acquisition sub-module 932 is used for obtaining data information according to the electric signal.

[0082] The data processing submodule 933 is connected with the data acquisition submodule 932.

[0083] The multi-channel erbium-doped fiber ultrasonic detection system can effectively realize simultaneous detection of multiple F-P ultrasonic sensors 6 in a ring laser.

[0084] As shown in Figure 5 , Figure 6 , it is a specific embodiment of the F-P ultrasonic sensor. The F-P ultrasonic sensor 6 is composed of a fiber ceramic plug and a fiber sleeve, and a circular silver film is pasted on the fiber sleeve.

[0085] Preferably, the thickness d of the circular silver film is 200 um, and the diameter D is 1 cm. The cavity length of the F-P ultrasonic sensor 6 is L. The cavity lengths of the F-P ultrasonic sensors 6 in each detection channel are different, thereby playing a filtering role.

[0086] The fiber at the end of the fiber ceramic plug and the circular silver film form an interference cavity of the F-P ultrasonic sensor, and the reflection formula is:

[0087]

[0088] where I r is the light intensity of reflected light, E r is the amplitude of reflected light, E in is the amplitude of incident light. M1 and M2 are two reflecting surfaces of the F-P ultrasonic sensor, and their reflectivities are R1 and R2, respectively. α1 is the transmission loss of the F-P ultrasonic sensor, and the phase delay φ = 2πnL / λ of a single pass is the phase change of the light beam after passing through the F-P cavity, where L and n are the length and refractive index of the F-P cavity, respectively, and λ is the wavelength.

[0089] The ultrasonic signal acts on the interference cavity of the F-P ultrasonic sensor, causing the spectrum to drift in the long-wave direction or the short-wave direction, and the sensitivity formula can be obtained as:

[0090]

[0091] Delta lambda is the wavelength shift of the F-P ultrasonic sensor reflection spectrum, delta X is the sound pressure change, and delta L is the cavity length change of the F-P ultrasonic sensor. The spectrum of the F-P ultrasonic sensor drifts with ultrasonic vibration, which will cause the output power of the modulated light signal to change.

[0092] The F-P ultrasonic sensors 6 are shared n, which are F-P1, F-P2,..., F-Pn respectively; the membrane disturbance of F-P1 will cause the power fluctuation of the modulated light signal of a corresponding wavelength, the membrane disturbance of F-P2 will cause the power fluctuation of the modulated light signal of a corresponding wavelength, and so on. Due to the effect of polarization hole burning, there is no crosstalk between the modulated light signals of multiple channels. Therefore, the multi-channel erbium-doped optical fiber ultrasonic detection system provided by the application can realize multi-channel ultrasonic detection.

[0093] The multi-channel erbium-doped optical fiber ultrasonic detection system provided by the application selects multiple F-P ultrasonic sensors 6 as filters and sensitive elements for ultrasonic detection, effectively utilizes the characteristics that the F-P sensor is more sensitive to ultrasonic, and has better response frequency, response sensitivity and response frequency band than the FBG sensor.

[0094] The embodiments in the specification are described in a progressive manner, and each embodiment focuses on the difference from other embodiments. The same or similar parts of each embodiment can be referred to each other. For the system disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple, and the related parts can be referred to the method part.

[0095] The principles and implementation modes of the application are described by applying specific examples in this paper, and the above embodiment description is only used to help understand the method of the application and its core idea; at the same time, for those skilled in the art, according to the idea of the application, the specific implementation mode and application range will be changed. In conclusion, the content of the specification should not be understood as a limitation of the application.

Claims

1. A multi-channel erbium-doped fiber ultrasonic detection system, characterized in that, The multi-channel erbium-doped fiber ultrasonic detection system is used for detecting an ultrasonic signal; the multi-channel erbium-doped fiber ultrasonic detection system comprises: an optical amplifier used for generating a multi-wavelength laser signal with stable energy; a polarizer connected with the optical amplifier and used for obtaining a polarized light signal according to the multi-wavelength laser signal; a first wavelength division multiplexer connected with the polarizer and used for dividing the polarized light signal into n beams according to different wavelengths to obtain n beams of branch light signals, wherein n is greater than or equal to 2; n detection channels, wherein each detection channel comprises: a polarization controller connected with the first wavelength division multiplexer and used for regulating a polarization state of a branch light signal output from the first wavelength division multiplexer; a circulator connected with the polarization controller and used for isolating and transmitting the branch light signal; an F-P ultrasonic sensor connected with the circulator and used for filtering the branch light signal to obtain a filtered light signal and performing acousto-optic modulation on the filtered light signal under the action of a to-be-detected ultrasonic signal to obtain a modulated light signal and return the modulated light signal to the circulator; the cavity lengths of the F-P ultrasonic sensors in the detection channels are different from each other; a second wavelength division multiplexer connected with the circulator in each detection channel and used for combining the modulated light signals to obtain a combined light signal; a coupling unit connected with the second wavelength division multiplexer and the optical amplifier and used for dividing the combined light signal into a first proportion light signal and a second proportion light signal according to energy proportions; the first proportion light signal is transmitted to the optical amplifier; a data processing unit connected with the coupling unit and used for obtaining a detection result of the to-be-detected ultrasonic signal according to the second proportion light signal.

2. The multi-channel, Er-doped fiber, ultrasound detection system of claim 1, wherein, The optical amplifier comprises: a pump source used for generating a light source signal; an erbium-doped fiber connected with the pump source and used for obtaining an incident light signal according to the light source signal; a third wavelength division multiplexer arranged between the pump source and the erbium-doped fiber and connected with the coupling unit and used for coupling the first proportion light signal and the light source signal and transmitting them to the erbium-doped fiber to obtain the multi-wavelength laser signal.

3. The multi-channel, Er-doped fiber, ultrasound detection system of claim 1, wherein, The data processing unit comprises: a coupling module connected with the coupling unit and used for dividing the second proportion light signal into a third proportion light signal and a fourth proportion light signal according to energy proportions; a spectrometer connected with the coupling module and used for obtaining an optical spectrum diagram under the action of the to-be-detected ultrasonic signal according to the third proportion light signal; a processing module connected with the coupling module and used for processing the fourth proportion light signal to obtain the detection result of the to-be-detected ultrasonic signal.

4. The multi-channel, Er-doped fiber, ultrasound detection system of claim 3, wherein, The processing module comprises: an optoelectronic conversion sub-module connected with the coupling module and used for obtaining an electric signal according to the third proportion light signal; a data acquisition sub-module connected with the optoelectronic conversion sub-module and used for obtaining data information according to the electric signal; a data processing sub-module connected with the data acquisition sub-module and used for processing the data information to obtain the detection result of the to-be-detected ultrasonic signal.

5. The multi-channel, Er-doped fiber, ultrasound detection system of claim 1, wherein, The coupling unit is a 9:1 coupler, and the combined optical signal is divided according to an energy ratio of 9:1; the energy ratio of the first proportion optical signal is 9, and the energy ratio of the second proportion optical signal is 1.

6. The multi-channel, Er-doped fiber, ultrasound detection system of claim 3, wherein, The coupling module is a 5:5 coupler, and the second proportion optical signal is divided according to an energy ratio of 5:5; the energy ratio of the third proportion optical signal is 5, and the energy ratio of the fourth proportion optical signal is 5.

7. The multi-channel, Er-doped fiber, ultrasound detection system of claim 2, wherein, The pump source is a 980nm laser.

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