Cable searching monitoring device integrating optical fiber cable accurate positioning and environment situation beforehand perception

Abstract

The invention provides a cable searching monitoring device integrating optical fiber cable accurate positioning and environment situation beforehand perception, which comprises a multi-wavelength light source, a first multi-wavelength WDM coupler, a first photoelectric detector, a second photoelectric detector, a third photoelectric detector and a to-be-detected optical fiber loop, and is characterized in that the first multi-wavelength WDM coupler is provided with a first beam splitting and combining unit and a second beam splitting and combining unit; the output end of the second beam splitting and combining unit is connected with the third photoelectric detector, the first beam splitting and combining unit is connected with the first photoelectric detector and the second photoelectric detector, the optical fiber loop to be detected is connected with the first beam splitting and combining unit and the second beam splitting and combining unit in series, and the optical fiber loop to be detected is provided with a port A and a port B; the first beam splitting and combining unit is provided with a first Sagnac interference structure, a first light path and a second light path. The optical cable external vibration sensing and positioning system has the advantages that the low-cost Sagnac interference technology principle is adopted, the optical cable external vibration sensing and positioning with the over 200 km performance of the ring topology are achieved, multiple functions are integrated, the convenience of the system can be greatly facilitated, the cost performance is high, and large-scale popularization is facilitated.

Description

Technical Field

[0001] The present invention mainly relates to the technical field of optical fiber communication management systems, and in particular to a cable-finding monitoring device that integrates precise positioning of optical fiber cables and advance perception of environmental situations. Background Art

[0002] At present, the length of optical cables in China has exceeded 65 million kilometers. Such a huge optical cable network is a passive infrastructure that is difficult to monitor and warn. Fault location and maintenance mainly rely on on-site inspections, which have complex procedures, high manpower investment, and long construction periods. For example, inter-provincial trunk lines have an average of about 6 interruptions per year for every 100 kilometers of optical cables, seriously affecting existing network services and systems; municipal splicing, road splicing, blocked back-up splicing, equipment splicing, route relocation, etc., plus natural disasters, performance degradation, various human factors, system failures, and other unknown reasons, will all lead to optical cable interruptions. Therefore, a cost-effective, fast, and accurate fault location method and pre-fault monitoring method are needed.

[0003] The inventor discovered the following defects during the operation of the specific embodiment: 1. Similar technical solutions for accurate positioning of optical cable faults are mainly based on the MZ interferometer optical cable route survey instrument, which can find faulty optical cables and conduct common optical cable surveys by touching or knocking on the faulty optical cable, listening to the sound restored by the system and the displayed optical power intensity signal; 2. Similar technical solutions for optical cable monitoring are mainly based on Phi-OTDR technology, and its basic structure and principle are as follows: The loss of light during transmission, part of which returns along the radial direction of the optical fiber in the form of random reflection, is called Rayleigh scattering; ordinary OTDR also detects Rayleigh scattered light, relying on the sudden change of optical power to determine the reflection point (abnormal increase of Rayleigh optical power) and the loss point (step decrease of Rayleigh optical power), but the coherence of the light source is poor, and the random interference change cannot be detected; Phi-OTDR uses a narrow linewidth light source, and the phase relationship of light in the same pulse is fixed. The leading edge of the pulse is transmitted to point a for reflection and the delay is transmitted to point b for reflection, and they reach the PD at the same time, causing interference. The spatial resolution of phi-OTDR does not exceed the pulse transmission distance / 2, and the optical phase is very sensitive to fiber vibration. When a certain part of the optical fiber is vibrated, the phase difference between the leading edge and the delay changes with time, resulting in the instability of the interference pattern over time. By detecting unstable interference, the location, intensity, and frequency of the vibration can be identified. However, the solution cost of Phi-OTDR is high, and the core components and modules are limited by production capacity and technical requirements, resulting in high prices, which is not conducive to large-scale promotion.

[0004] It should be noted that the above contents belong to the technical cognition scope of the inventor. Since the technical contents in this field are vast and too complicated, the above contents of this application do not necessarily constitute prior art. Summary of the invention

[0005] 1. Technical problems to be solved by the invention: The cable-finding monitoring device provided by the present invention integrates precise positioning of optical fiber cables and pre-perception of environmental situations, and is used to solve the technical problems existing in the above-mentioned background technologies.

[0006] 2. Technical solution: To achieve the above-mentioned purpose, the present invention provides a cable-finding monitoring device that integrates precise positioning of optical fiber and cable and pre-perception of environmental situations, comprising a multi-wavelength light source, a multi-wavelength WDM coupler 1, a photodetector 1, a photodetector 2, a photodetector 3 and an optical fiber loop to be tested, wherein the multi-wavelength WDM coupler 1 has a beam splitting and combining unit 1 and a beam splitting and combining unit 2, the output end of the beam splitting and combining unit 2 is connected to the photodetector 3, the beam splitting and combining unit 1 is respectively connected to the photodetector 1 and the photodetector 2, the optical fiber loop to be tested is connected in series with the beam splitting and combining unit 1 and the beam splitting and combining unit 2, the optical fiber loop to be tested has an A port and a B port, the beam splitting and combining unit 1 has a Sagnac interference structure 1, an optical path 1 and an optical path 2, the Sagnac interference structure 1 is respectively connected to the photodetector 1 and the photodetector 2 through a dual-wavelength WDM coupler 5, the beam splitting and combining unit 2 has a Sagnac interference structure 2, and the Sagnac interference structure 2 is connected to the photodetector 3.

[0007] Furthermore, the Sagnac interference structure 1 includes a four-port coupler 1, a light coil 1 and a four-port coupler 2.

[0008] Furthermore, the optical path 1 includes an isolator 1, a dual-wavelength WDM coupler 1, a dual-wavelength WDM coupler 2, and a multi-wavelength WDM coupler 2.

[0009] Furthermore, the optical path 2 includes an isolator 2, a dual-wavelength WDM coupler 3, a dual-wavelength WDM coupler 4 and a multi-wavelength WDM coupler 3, and the dual-wavelength WDM coupler 4 is connected in series with the dual-wavelength WDM coupler 1, the dual-wavelength WDM coupler 3 and the multi-wavelength WDM coupler 3.

[0010] Furthermore, the second multi-wavelength WDM coupler and the third multi-wavelength WDM coupler are connected to the A port and the B port respectively.

[0011] Furthermore, the second Sagnac interference structure includes a third four-port coupler, a second light coil and a three-port coupler, and the three-port coupler is connected to the second multi-wavelength WDM coupler.

[0012] Furthermore, the four-port coupler three is connected to the multi-wavelength WDM coupler one and the photodetector three respectively.

[0013] 3. Beneficial effects: Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects: The present invention is reasonably designed and adopts the low-cost Sagnac interference technology principle to achieve high-performance external vibration sensing and positioning of optical cables over 200km in a ring topology. It integrates multiple functions in one, which can greatly facilitate the convenience and high cost-effectiveness of the system and facilitate large-scale promotion. 1. Greatly simplify the cost and detection distance of the existing optical cable environment situation awareness system. Compared with the traditional one-way Phi-OTDR vibration positioning system, it has advantages in cost and measurement length. The cost is one order of magnitude lower and the measurement length is doubled; 2. It can realize accurate optical cable census function, and realize optical path census through non-contact vibration sensing combined with vibration positioning; 3. Regardless of whether the optical cable is interrupted or not, the function of accurately finding the cable can be achieved.

[0014] It should be noted that the structures not introduced in the present invention are the same as the prior art or can be implemented by using the prior art, and are not described in detail here because they do not involve the design points and improvement directions of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the cable-finding monitoring device of the present invention that integrates precise positioning of optical fiber cables and pre-awareness of environmental situations based on different wavelengths; Figure 2 It is a schematic diagram of the cable-finding monitoring device of the present invention which integrates precise positioning of optical fiber cables and pre-awareness of environmental situations based on a wide-spectrum light source.

[0016] Reference numerals: 1. Multi-wavelength light source; 2. Photodetector 1; 3. Multi-wavelength WDM coupler 1; 4. Photodetector 2; 5. Four-port coupler 1; 6. Light volume 1; 7. Four-port coupler 2; 8. Isolator 1; 9. Isolator 2; 10. Dual-wavelength WDM coupler 1; 11. Dual-wavelength WDM coupler 3; 12. Dual-wavelength WDM coupler 4; 13. Dual-wavelength WDM coupler 2; 14. Photodetector 3; 15. Four-port coupler 3; 16. Light volume 2; 17. Three-port coupler; 18. Multi-wavelength WDM coupler 2; 19. Dual-wavelength WDM coupler 5; 20. Multi-wavelength WDM coupler 3; 21. Optical fiber loop to be tested. DETAILED DESCRIPTION

[0017] To facilitate understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Several embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0018] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "page", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicating orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0019] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0020] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed", "provided with", "provided on" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. Example

[0021] See attached Figure 1-2 The cable-finding monitoring device for integrating precise positioning of optical fiber and cable and pre-perception of environmental situation provided by the present invention comprises a multi-wavelength light source 1, a multi-wavelength WDM coupler 13, a photodetector 12, a photodetector 24, a photodetector 3 14 and an optical fiber loop 21 to be tested, wherein the multi-wavelength WDM coupler 13 has a beam splitting and combining unit 1 and a beam splitting and combining unit 2, the output end of the beam splitting and combining unit 2 is connected to the photodetector 3 14, the beam splitting and combining unit 1 is respectively connected to the photodetector 1 2 and the photodetector 2 4, the optical fiber loop 21 to be tested is connected in series with the beam splitting and combining unit 1 and the beam splitting and combining unit 2, the optical fiber loop 21 to be tested has an A port and a B port, the beam splitting and combining unit 1 has a Sagnac interference structure 1, an optical path 1 and an optical path 2, the Sagnac interference structure 1 is respectively connected to the photodetector 1 2 and the photodetector 2 4 through a dual-wavelength WDM coupler 5 19, the beam splitting and combining unit 2 has a Sagnac interference structure 2, and the Sagnac interference structure 2 is connected to the photodetector 3 14.

[0022] The Sagnac interference structure 1 includes a four-port coupler 1 5 , a light coil 1 6 and a four-port coupler 2 7 .

[0023] Optical path one includes isolator one 8, dual-wavelength WDM coupler one 10, dual-wavelength WDM coupler two 13, and multi-wavelength WDM coupler two 18.

[0024] Optical path two includes isolator two 9, dual-wavelength WDM coupler three 11, dual-wavelength WDM coupler four 12 and multi-wavelength WDM coupler three 20. Dual-wavelength WDM coupler four 12 is connected in series with dual-wavelength WDM coupler one 10, dual-wavelength WDM coupler three 11 and multi-wavelength WDM coupler three 20.

[0025] The second multi-wavelength WDM coupler 18 and the third multi-wavelength WDM coupler 20 are connected to the A port and the B port respectively.

[0026] The second Sagnac interference structure includes a third four-port coupler 15 , a second light coil 16 , and a three-port coupler 17 . The three-port coupler 17 is connected to a second multi-wavelength WDM coupler 18 .

[0027] The four-port coupler 15 is connected to the multi-wavelength WDM coupler 1 3 and the photodetector 3 14 respectively.

[0028] Embodiment 1, refer to the attached Figure 1 , the spectrum light emitted by the multi-wavelength light source 1 is divided into three wavelength lights ƛ1, ƛ2, ƛ3, which are injected into the multi-wavelength WDM coupler 1 3 and divided into two paths. The specific working process is as follows: Among them, ƛ1 and ƛ2 pass through the Sagnac interference structure 1 (four-port coupler 15 + light coil 16 and the direct-connected optical fiber under the optical fiber coil + four-port coupler 2 7), through the one-way isolator 18 to reach the dual-wavelength WDM coupler 10, and are divided into two paths of light with different wavelengths again; A light beam ƛ1 is injected from the dual-wavelength WDM coupler 2 13 and the multi-wavelength WDM coupler 2 18 (integrated with ƛ3) into the A port of the optical fiber loop 21 to be tested, comes back through the B port, is injected into the multi-wavelength WDM coupler 3 20, the dual-wavelength WDM coupler 4 12, and the dual-wavelength WDM coupler 3 11, passes through the unidirectional isolator 2 9 to reach the Sagnac interference structure 1 (the four-port coupler 1 5 + the optical fiber roll 1 6 and the direct-connected optical fiber under the optical fiber roll + the four-port coupler 2 7), and then from the dual-wavelength WDM coupler 5 19 to the photodetector 1 2; Another light path ƛ2 is injected from the dual-wavelength WDM coupler 10, the dual-wavelength WDM coupler 4 12 and the multi-wavelength WDM coupler 3 20 into the B port of the optical fiber loop 21 to be tested, comes back through the A port, is injected into the multi-wavelength WDM coupler 2 18, the dual-wavelength WDM coupler 2 13, the dual-wavelength WDM coupler 3 11, passes through the unidirectional isolator 2 9 to reach the Sagnac interference structure 1 (four-port coupler 1 5 + optical fiber roll 1 6 and the direct-connected optical fiber under the optical fiber roll + four-port coupler 2 7), and reaches the photodetector 2 4 from the dual-wavelength WDM coupler 5 19; The last path ƛ3 passes through Sagnac interference structure 2 (four-port coupler 3 15 + light coil 2 16 and the direct-connected optical fiber under the optical fiber coil + three-port coupler 17), and is injected from multi-wavelength WDM coupler 2 18 into port A of the optical fiber loop 21 to be tested. The reflected signal at any point on the optical fiber loop 21 to be tested returns through port A, passes through multi-wavelength WDM coupler 2 18, and reaches Sagnac interference structure 2 (four-port coupler 3 15 + light coil 2 16 and the direct-connected optical fiber under the optical fiber coil + three-port coupler 17), and reaches photodetector 3 14.

[0029] If vibration occurs at any point of the optical fiber loop 21 to be tested, the vibration will cause the refractive index of the optical fiber to change through the optical fiber Kerr effect, thereby causing the phase of the optical signal to change, and the intensity of the optical signal to change after Sagnac interference. Therefore, the above two optical paths ƛ1 and ƛ2 can detect the change of optical power intensity caused by the vibration change at any point in the entire optical path to be tested. Because in the loop structure, the optical path difference of the two optical paths is different for the same vibration point, the time difference of the vibration sensed by the detection circuit behind the two optical paths can accurately locate the position of the vibration in the entire optical path to be tested.

[0030] At the same time, any change in the vibration point is returned to the photodetector three 14 through the backscattered signal at the vibration point via the optical path of ƛ3, thereby realizing accurate detection of the faulty optical cable under the premise that the optical cable is interrupted (at this time, the optical cables of ƛ1 and ƛ2 do not work due to isolator one 8 and isolator two 9).

[0031] Under the premise of non-optical cable route interruption: ƛ1, ƛ2, ƛ3 three optical paths can realize accurate cable locating. At the same time, ƛ1 and ƛ2 can also realize accurate positioning of the optical cable environment status. Under the premise of optical cable interruption, ƛ3 is a multifunctional all-in-one device that can realize accurate faulty optical cable locating.

[0032] Note that the above-mentioned light sources of different wavelengths may be a single light source with different wavelengths, or may be multiple light sources, each with a different wavelength. As long as different wavelengths can be achieved, they can be implemented within the present technical solution.

[0033] Embodiment 2, refer to the attached Figure 2 In the case of a further step in the above-mentioned embodiment one, the multi-wavelength light sources ƛ1, ƛ2, ƛ3, etc. shown can also be replaced by multiple bands B1, B2, B3 of a spectral light source. Compared with the embodiment one, the biggest difference is that the multi-wavelength light source 1 is changed into a spectral light source, and the WDM couplers ƛ1, ƛ2, ƛ3 of different wavelengths are changed into red and blue band couplers B1, B2, B3 of multi-spectral bandwidth.

[0034] In summary, the ring structure solution based on Sagnac interferometric positioning can realize a systematic solution for accurate cable finding and optical cable environmental status monitoring; the two major types of Sagnac interferometric positioning (broad-spectrum light source and multi-wavelength light source) can meet the system design needs with different performance parameters and costs.

[0035] The above-described embodiments only express a certain implementation mode of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the patent scope of the present invention. It should be pointed out that, for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.

Claims

1. A cable-finding monitoring device that integrates precise positioning of optical fiber cables and pre-awareness of environmental situations, characterized by: The invention comprises a multi-wavelength light source (1), a multi-wavelength WDM coupler 1 (3), a photodetector 1 (2), a photodetector 2 (4), a photodetector 3 (14) and an optical fiber loop (21) to be tested, wherein the multi-wavelength WDM coupler 1 (3) comprises a beam splitting and combining unit 1 and a beam splitting and combining unit 2, the output end of the beam splitting and combining unit 2 is connected to the photodetector 3 (14), the beam splitting and combining unit 1 is connected to the photodetector 1 (2) and the photodetector 2 (4), respectively, and the optical fiber loop (21) to be tested is connected to the beam splitting and combining unit 2. The beam-bundling unit 1 and the beam-splitting and beam-combining unit 2 are connected in series, the optical fiber loop (21) to be tested has an A port and a B port, the beam-splitting and beam-combining unit 1 has a Sagnac interference structure 1, an optical path 1 and an optical path 2, the Sagnac interference structure 1 is respectively connected to the photodetector 1 (2) and the photodetector 2 (4) through a dual-wavelength WDM coupler 5 (19), the beam-splitting and beam-combining unit 2 has a Sagnac interference structure 2, and the Sagnac interference structure 2 is connected to the photodetector 3 (14).

2. The cable-finding monitoring device integrating precise positioning of optical fiber and cable and pre-awareness of environmental situation according to claim 1 is characterized in that: The Sagnac interference structure 1 includes a four-port coupler 1 (5), a light coil 1 (6) and a four-port coupler 2 (7).

3. The cable-finding monitoring device integrating precise positioning of optical fiber and cable and pre-awareness of environmental situation according to claim 1 is characterized by: The optical path one comprises an isolator one (8), a dual-wavelength WDM coupler one (10), a dual-wavelength WDM coupler two (13), and a multi-wavelength WDM coupler two (18).

4. The cable-finding monitoring device integrating precise positioning of optical fiber and cable and pre-awareness of environmental situation according to claim 3 is characterized by: The optical path 2 comprises an isolator 2 (9), a dual-wavelength WDM coupler 3 (11), a dual-wavelength WDM coupler 4 (12) and a multi-wavelength WDM coupler 3 (20); the dual-wavelength WDM coupler 4 (12) is connected in series with the dual-wavelength WDM coupler 1 (10), the dual-wavelength WDM coupler 3 (11) and the multi-wavelength WDM coupler 3 (20).

5. The cable-finding monitoring device integrating precise positioning of optical fiber and cable and pre-awareness of environmental situation according to claim 4 is characterized by: The second multi-wavelength WDM coupler (18) and the third multi-wavelength WDM coupler (20) are connected to the A port and the B port respectively.

6. The cable-finding monitoring device integrating precise positioning of optical fiber and cable and pre-awareness of environmental situation according to claim 5 is characterized by: The second Sagnac interference structure comprises a third four-port coupler (15), a second light coil (16) and a three-port coupler (17), wherein the three-port coupler (17) is connected to the second multi-wavelength WDM coupler (18).

7. The cable-finding monitoring device integrating precise positioning of optical fiber and cable and pre-awareness of environmental situation according to claim 6 is characterized by: The four-port coupler three (15) is connected to the multi-wavelength WDM coupler one (3) and the photodetector three (14) respectively.

Images