CN117975636A - Quasi-distributed vibration alarm optical fiber system based on coarse wavelength division multiplexing - Google Patents

Quasi-distributed vibration alarm optical fiber system based on coarse wavelength division multiplexing Download PDF

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Publication number
CN117975636A
CN117975636A CN202311509236.3A CN202311509236A CN117975636A CN 117975636 A CN117975636 A CN 117975636A CN 202311509236 A CN202311509236 A CN 202311509236A CN 117975636 A CN117975636 A CN 117975636A
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China
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wavelength division
port
sensing
optical fiber
output
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CN202311509236.3A
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周柯江
叶炜
徐正国
陈健
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Huzhou Institute of Zhejiang University
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Huzhou Institute of Zhejiang University
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Priority to CN202311509236.3A priority Critical patent/CN117975636A/en
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    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B13/00—Burglar, theft or intruder alarms
    • G08B13/18—Actuation by interference with heat, light, or radiation of shorter wavelength; Actuation by intruding sources of heat, light, or radiation of shorter wavelength
    • G08B13/181—Actuation by interference with heat, light, or radiation of shorter wavelength; Actuation by intruding sources of heat, light, or radiation of shorter wavelength using active radiation detection systems
    • G08B13/187—Actuation by interference with heat, light, or radiation of shorter wavelength; Actuation by intruding sources of heat, light, or radiation of shorter wavelength using active radiation detection systems by interference of a radiation field
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B13/00—Burglar, theft or intruder alarms
    • G08B13/02—Mechanical actuation
    • G08B13/12—Mechanical actuation by the breaking or disturbance of stretched cords or wires
    • G08B13/122—Mechanical actuation by the breaking or disturbance of stretched cords or wires for a perimeter fence
    • G08B13/124—Mechanical actuation by the breaking or disturbance of stretched cords or wires for a perimeter fence with the breaking or disturbance being optically detected, e.g. optical fibers in the perimeter fence

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)

Abstract

The invention discloses a quasi-distributed optical fiber vibration alarm system based on coarse wavelength division multiplexing, which adopts ultra-wide spectrum light source output light, and the light is output through a single-mode optical fiber circulator, and sequentially passes through n-1 input ports-transmission ports of three-port coarse wavelength division multiplexers with different reflection bands, and the output of the reflection port of each three-port coarse wavelength division multiplexer passes through a1 multiplied by 2 single-mode coupler, left and right sensing optical cables, an optical fiber depolarization and a delay ring to form a Sagnac interferometer. The sensing optical cable is changed in asymmetric phase caused by external vibration signals, two beams of light are interfered and then returned to the third end of the single-mode optical fiber circulator according to an original light path to be output, the third end of the circulator is connected with a1 xnACG coarse division multiplexing device, n paths of interference light with different wavelengths are separated, each path of output light is connected with a photoelectric detector, the optical interference signals are changed into electric signals, and the electric signals are amplified, collected, mode-identified and transmitted to an upper computer and output to alarm by a subsequent signal processing unit, so that a quasi-distributed vibration alarm optical fiber system is formed.

Description

Quasi-distributed vibration alarm optical fiber system based on coarse wavelength division multiplexing
Technical Field
The invention relates to a vibration alarm optical fiber system, in particular to a quasi-distributed vibration alarm optical fiber system based on coarse wavelength division multiplexing.
Background
The fiber Sagnac interference ring can be used for forming a vibration alarm sensor with stable performance, and the principle is that a stress is applied to a section of optical cable far away from the midpoint of the Sagnac interference ring, so that the refractive index and the length of the optical fiber are changed, and the output of an interference signal is changed. If it is desired to use such a sensor to form a quasi-separate vibration alarm system, it would be desirable to divide a light source into n beams of light using 1*n splitters, each beam of light being formed by connecting a Sagnac fiber optic interference ring with a different length of fiber optic cable, which is suitable for use in forming a star-type sensing system. But it is very inconvenient to compose a linear or annular sensing system, which is the most common form in the field of safety protection.
In addition, it is noted that to achieve high stability and low noise output of the Sagnac interferometer, the use of a broad spectrum light source is currently the most mature and reliable solution.
Disclosure of Invention
Because of the problems in the prior art, the invention provides a quasi-distributed vibration alarm optical fiber system based on coarse wavelength division multiplexing, which adopts an ultra-wideband light source and a coarse wavelength division multiplexing device, so that the low-loss requirements of a plurality of interferometer channels are solved, and the problem of a wide-spectrum light source required by a Sagnac interferometer is also solved.
In order to solve the problems, the technical solution of the invention is as follows:
A quasi-distributed vibration alarm optical fiber system based on coarse wavelength division multiplexing comprises an ultra-wide spectrum light source, a single-mode fiber circulator, 1*n coarse wavelength division multiplexers, a photoelectric detector group consisting of n photoelectric detectors and n-1 three-port coarse wavelength division multiplexers; the system adopts light output by an ultra-wide spectrum light source, the light is output by the single-mode fiber circulator and sequentially passes through the input port-transmission port of n-1 three-port coarse division multiplexers with different reflection bands, and the reflection port output of each three-port coarse division multiplexer passes through a1 multiplied by 2 single-mode coupler, left and right sensing optical cables and an optical fiber depolarization and delay ring to form a Sagnac interferometer; the sensing optical cable is changed in asymmetric phase caused by external vibration signals, two beams of light are returned to the third port of the single-mode fiber circulator for output according to an original light path after interference, the third port of the single-mode fiber circulator is connected with the 1*n coarse division multiplexer, n paths of interference light with different wavelengths are separated, each path of output light is connected with one photoelectric detector in the photoelectric detector group, the optical interference signals are changed into electric signals, and the electric signals are amplified, collected, mode-identified and transmitted to an upper computer and output alarm by a subsequent signal processing unit to form a quasi-distributed vibration alarm optical fiber system.
Further, the ultra-wide spectrum light source is connected with a first input end of a single-mode fiber circulator, a second output end of the fiber circulator is connected to a total light path of the system, and an output end of the single-mode fiber circulator is connected with an input end of the 1*n coarse division multiplexer; the n output ends of the 1*n coarse division multiplexer are respectively connected with n detectors of the photoelectric detector group, and the photoelectric detector group changes optical signals into n paths of electric signals; and on the total optical path, n-1 three-port coarse division multiplexers with different reflection center wavelengths and the same bandwidth are sequentially connected.
Further, the input end of the first three-port coarse division multiplexer is connected to the second output end of the optical fiber circulator through the total optical path, the pass-through end of the first three-port coarse division multiplexer is connected to the input end of the second three-port coarse division multiplexer, the pass-through end of the second three-port coarse division multiplexer is connected to the input end of the third three-port coarse division multiplexer …, and so on.
Further, the reflecting end of the first three-port coarse division multiplexer is connected with the input end of the first 1*2 single-mode fiber coupler, two output ends of the first 1*2 single-mode fiber coupler are respectively connected with one ends of a first sensing optical cable and a second sensing optical cable, and the other ends of the first sensing optical cable and the second sensing optical cable are respectively connected with two ports of a first optical fiber depolarization and delay line; the reflection end of the second three-port coarse division multiplexer is connected with the input end of the second 1*2 single-mode fiber coupler, the two output ends of the second 1*2 single-mode fiber coupler are respectively connected with one ends of a third sensing optical cable and a fourth sensing optical cable, the other ends of the third sensing optical cable and the fourth sensing optical cable are respectively connected with two ports of a second optical fiber depolarization and delay line, and the like, the last three-port coarse division multiplexer connected is omitted, the total optical path is directly connected with the input end of the n1 x2 single-mode fiber coupler, the two output ends of the n1 x2 single-mode fiber coupler are respectively connected with one ends of a 2n-1 sensing optical cable and a 2n sensing optical cable, and the other ends of the 2n-1 sensing optical cable and the 2n sensing optical cable are respectively connected with the two ports of the n optical fiber depolarization and delay line.
Further, the first sensing optical cable and the second sensing optical cable are respectively arranged at the left side and the right side of the sensing position or are arranged at the same side in a differential mode; the third sensing optical cable and the fourth sensing optical cable are respectively arranged at the left side and the right side of the sensing position or are arranged at the same side in a differential mode; … … and so on, the 2n-1 th sensing optical cable and the 2n th sensing optical cable are respectively arranged at the left side and the right side of the sensing position or are arranged at the same side in a differential mode.
Further, the lengths of the first sensing optical cable and the second sensing optical cable are far shorter than the lengths of the first optical fiber depolarization and the delay line; the lengths of the third sensing optical cable and the fourth sensing optical cable are far shorter than the lengths of the second optical fiber depolarization and the delay line; … …, and so on, the lengths of the 2n-1 sensing optical cable and the 2n sensing optical cable are far shorter than the lengths of the n optical fiber depolarization and delay line.
Further, the n-1 three-port coarse division multiplexer is formed by adopting a micro-optical collimating lens and an interference filter.
Further, the 1*n coarse division multiplexer adopts an AWG structure, and each optical path output wave band corresponds to the reflection spectrum of each three-port coarse division multiplexer.
Further, the ultra-wide spectrum light source is provided with an ultra-radiation light source with the width of tens of nm, a semiconductor laser is adopted to pump an active optical fiber to generate wide-spectrum fluorescence, and ultra-wide spectrum light output is obtained through an isolator and a special filter; the ultra-wide spectrum light source adopts a semiconductor super-radiation diode for output.
The beneficial effects obtained by the invention are as follows:
The invention relates to a single-light-path optical fiber vibration alarm system based on a coarse wavelength division multiplexing device, wherein n Sagnac optical fiber interferometers are arranged along a total light path to form a quasi-distributed linear or annular sensor system, the Sagnac optical fiber interferometers can reach higher stability and excellent signal to noise ratio by adopting a wide-spectrum light source, the output of each optical fiber coarse division filter is connected with one Sagnac interferometer by adopting a low-loss optical fiber coarse division filter with n different wave bands sequentially, the sensing optical fiber is changed in asymmetric phase by an external vibration signal on the Sagnac optical interferometers, a receiving end adopts a 1*n coarse division multiplexing device to separate n paths of interference light with different wavelengths, and the optical interference signal is changed into n electrical signals by adopting a photoelectric detector group, and is amplified, collected, mode-identified and transmitted to an upper computer by a subsequent signal processing unit to form the quasi-distributed vibration alarm optical fiber system.
Drawings
FIG. 1 is a block diagram of a quasi-distributed vibration alarm fiber system based on a coarse wavelength division multiplexing device
Reference numerals: ultra-wideband light source: 1, a step of; single mode fiber circulator: 2, single mode fiber circulator 2 first port: 2-1, second port: 2-2, a third port 2-3;1*n coarse division multiplexer: 3,1×n coarse multiplexer 3 first output port: 3-1, a second output port 3-2, … …, an nth output port: 3-3; photodetector group: 4, a first detector: 4-1, a second detector: 4-2, … …, nth detector: 4-3; a first three-port coarse division multiplexer: 5, three-port coarse division multiplexer 5 input port: 5-1, reflection port: 5-2, transmissive ports: 5-3; first 1×2 fiber coupler: 6, preparing a base material; a first sensing optical cable: 7, preparing a base material; a second sensing optical cable: 8, 8; a first optical fiber depolarization and delay line 9; a second three-port coarse division multiplexer: three-port coarse multiplexer 10 input port: 10-1, reflection port: 10-2, transmissive port: 10-3;1 x 2 fiber coupler: 11; third sensing optical cable: 12; fourth sensing optical cable: 13; a second fiber depolarization and delay line 14; … …; nth 1×2 fiber coupler: 15; 2n-1 sensing optical cable: 16; 2 n-th sensing optical cable: 17; 18, fiber depolarization and delay line.
The specific embodiment is as follows:
In order to make the description of the objects, technical solutions, advantages and the like of the present invention clearer and more accurate, the following describes in detail embodiments of the present invention, examples of which are given in the form of accompanying drawings. The exemplary embodiments of the invention and their description are specifically illustrated herein for the purpose of explanation and not for limitation of the design of the present invention.
The invention relates to a quasi-distributed vibration alarm optical fiber system based on coarse wavelength division multiplexing, which comprises an ultra-wide spectrum light source 1, a single-mode fiber circulator 2, 1*n coarse wavelength division multiplexer 3, a photoelectric detector group 4 consisting of n photoelectric detectors and n-1 three-port coarse wavelength division multiplexers (5), (10) …; the system adopts light output by an ultra-wide spectrum light source 1, the light is output by a single-mode fiber circulator 2, the light sequentially passes through n-1 input ports-transmission ports of three-port coarse division multiplexers with different reflection bands, and the reflection port output of each three-port coarse division multiplexer passes through a 1X 2 single-mode coupler, left and right sensing optical cables and an optical fiber depolarization and delay ring to form a Sagnac interferometer; the sensing optical cable is changed in asymmetric phase caused by external vibration signals, two beams of light are interfered and then returned to a third port of the single-mode optical fiber circulator 2 for output according to an original light path, the third port of the single-mode optical fiber circulator 2 is connected with a 1*n coarse-division multiplexer 3, n paths of interference light with different wavelengths are separated, each path of output light is connected with one photoelectric detector in the photoelectric detector group 4, the optical interference signals are changed into electric signals, and the electric signals are amplified, collected, mode-identified and transmitted to an upper computer and output alarm by a subsequent signal processing unit to form a quasi-distributed vibration alarm optical fiber system.
Example 1
Fig. 1 is a block diagram of an optical fiber vibration sensing system using a coarse division multiplexing device. Specifically, a 1550nm wave band device is sampled, and an ultra-wide spectrum light source 1 adopts a flat spectrum optical fiber light source ASE with the bandwidth of 40 nm; the single-mode fiber circulator 2 adopts a single-mode device, the 1*n coarse division multiplexer 3 adopts a 1*8-port AWG device, and the bandwidth is 5nm. 8 PIN-FETs are adopted as the photoelectric detector group 4; the three-port coarse division multiplexer 5 and the three-port coarse division multiplexer 10 … … have 7 different reflection center wavelengths, and the film reflection bandwidth is 5nm;1×2 fiber couplers 6, 1×2 fiber couplers 11, … …,1×2 fiber coupler 15, 8 fiber couplers in total; the first sensing optical cable 7, the second sensing optical cable 8, the third sensing optical cable 12, the fourth sensing optical cables 13 and … …, the 2n-1 sensing optical cable 16 and the 2n sensing optical cable 17 are all 16 sections of sensing optical fibers, and each section of sensing optical fiber has the length of 200 meters. The first optical fiber depolarization and delay line 9, the second optical fiber depolarization and delay lines 14 and … … and the nth optical fiber depolarization and delay line 18 are 8, and a single-mode bare optical fiber with the length of 1 km is used for winding a ring with a small enough radius to achieve the effects of delay and depolarization. The quasi-distributed optical fiber vibration alarm system with the length of 1.6 km is composed of the components, a circuit and a computer.
Example 2
Fig. 1 is a block diagram of an optical fiber vibration sensing system using a coarse division multiplexing device. Specifically, a 1310nm wave band device is sampled, and an ultra-wide spectrum light source 1 adopts an ultra-radiation diode SLD with the bandwidth of 50 nm; the single-mode fiber circulator 2 adopts a single-mode device, the 1*n coarse division multiplexer 3 adopts a 1*5-port AWG device, and the bandwidth is 10nm. 5 PIN-FETs are adopted as the photoelectric detector group 4; the first three-port coarse division multiplexer 5 and the second three-port coarse division multiplexer 10 … … are three-port coarse division multiplexers with 4 different reflection center wavelengths, and the film reflection bandwidth is 10nm; the first 1×2 optical fiber coupler 6, the second 1×2 optical fiber couplers 11, … …, and the nth 1×2 optical fiber coupler 15 are 5 optical fiber couplers in total; the first sensing optical cable 7, the second sensing optical cable 8, the third sensing optical cable 12, the fourth sensing optical cables 13 and … …, the 2n-1 sensing optical cable 16 and the 2n sensing optical cable 17 are 10 sections of sensing optical fibers, and each section is 200 meters in length. The first optical fiber depolarization and delay line 9, the second optical fiber depolarization and delay lines 14 and … … and the nth optical fiber depolarization and delay line 18 are 5, and a single-mode bare optical fiber with the length of 1 km is used for winding a ring with a small enough radius to achieve the effects of delay and depolarization. The quasi-distributed optical fiber vibration alarm system with the length of 1 km is composed of the components, a circuit and a computer.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention.

Claims (9)

1. The quasi-distributed vibration alarm optical fiber system based on coarse wavelength division multiplexing is characterized by comprising an ultra-wide spectrum light source (1), a single-mode fiber circulator (2), 1*n coarse wavelength division multiplexers (3), a photoelectric detector group (4) consisting of n photoelectric detectors and n-1 three-port coarse wavelength division multiplexers (5) (10) …;
The system adopts light output by an ultra-wide spectrum light source (1), the light is output by a single-mode fiber circulator (2), the light sequentially passes through n-1 input ports-transmission ports of three-port coarse-division multiplexers (5) (10) … with different reflection bands, and the output of the reflection port of each three-port coarse-division multiplexer passes through a 1X 2 single-mode coupler, left and right sensing optical cables and an optical fiber depolarization and delay ring to form a Sagnac interferometer; the sensing optical cable is changed by asymmetric phases caused by external vibration signals, two beams of light are returned to a third port of the single-mode fiber circulator (2) for output according to an original light path after interference, the third port of the single-mode fiber circulator (2) is connected with the 1*n coarse division multiplexer (3), n paths of interference light with different wavelengths are separated, each path of output light is connected with one photoelectric detector in the photoelectric detector group, the optical interference signals are changed into electric signals, and the electric signals are amplified, collected, mode-identified and transmitted to an upper computer and output alarm by a subsequent signal processing unit, so that a quasi-distributed vibration alarm optical fiber system is formed.
2. A quasi-distributed vibration alarm fiber system based on coarse wavelength division multiplexing as defined in claim 1, wherein,
The ultra-wide spectrum light source (1) is connected with a first input end (2-1) of the single-mode fiber circulator (2), a second output end (2-2) of the single-mode fiber circulator (2) is connected to a total light path of the system, and an output end (2-3) of the single-mode fiber circulator (2) is connected with an input end of the 1*n coarse division multiplexer (3); the n outputs (3-1) (3-2) … (3-3) of the 1*n coarse multiplexer (3) and the n detectors (4-1) of the photodetector group (4)
(4-2) … (4-3) Respectively connected, wherein the photoelectric detector group (4) changes the optical signal into n paths of electric signals; on the total optical path, n-1 three-port coarse division multiplexers (5), (10) and … with different reflection center wavelengths and the same bandwidth are connected in sequence.
3. A quasi-distributed vibration alarm fiber system based on coarse wavelength division multiplexing according to claim 1, wherein the input end (5-1) of the first three-port coarse wavelength division multiplexer (5) is connected to the second output end (2-2) of the single-mode fiber circulator via the total optical path, the pass end (5-3) of the first three-port coarse wavelength division multiplexer (5) is connected to the input end (10-1) of the second three-port coarse wavelength division multiplexer (10), the pass end (10-3) of the second three-port coarse wavelength division multiplexer (10) is connected to the input end of the third three-port coarse wavelength division multiplexer …, and so on.
4. A quasi-distributed vibration alarm optical fiber system based on coarse wavelength division multiplexing according to claim 3, wherein the reflecting end (5-2) of the first three-port coarse wavelength division multiplexer (5) is connected with the input end of the first 1*2 single-mode optical fiber coupler (6), two output ends of the first 1*2 single-mode optical fiber coupler (6) are respectively connected with one ends of the first sensing optical cable (7) and the second sensing optical cable (8), and the other ends of the first sensing optical cable (7) and the second sensing optical cable (8) are respectively connected with two ports of the first optical fiber depolarization and delay line (9); the reflection end (10-2) of the second three-port coarse wavelength division multiplexer (10) is connected with the input end of the second 1*2 single-mode fiber coupler (11), two output ends of the second 1*2 single-mode fiber coupler (11) are respectively connected with one ends of the third sensing optical cable (12) and the fourth sensing optical cable (13), the other ends of the third sensing optical cable (12) and the fourth sensing optical cable (13) are respectively connected with two ports … … of the second optical fiber depolarization and delay line (14), the last three-port coarse wavelength division multiplexer connected is omitted, the total optical path is directly connected with the input end of the n1 x 2 single-mode fiber coupler (15), two output ends of the n1 x 2 single-mode fiber coupler (15) are respectively connected with one ends of the 2n-1 sensing optical cable (16) and the 2n sensing optical cable (17), and the other ends of the 2n-1 sensing optical cable (16) and the 2n sensing optical cable (17) are respectively connected with the two ports of the n optical fiber depolarization and delay line (18).
5. A quasi-distributed vibration alarm optical fiber system based on coarse wavelength multiplexing according to claim 4, wherein the first and second sensing optical fiber cables (7, 8) are arranged on the left and right sides of the sensing location, respectively, or are arranged on the same side in differential form; the third sensing optical cable (12) and the fourth sensing optical cable (13) are respectively arranged at the left side and the right side of the sensing position or are arranged at the same side in a differential mode; … … and so on, the 2n-1 th sensing optical cable (16) and the 2n th sensing optical cable (17) are respectively arranged at the left side and the right side of the sensing position or are arranged at the same side in a differential mode.
6. A quasi-distributed vibration alert fiber optic system based on coarse wavelength multiplexing according to claim 4, characterized in that the length of both the first sensing fiber optic cable (7) and the second sensing fiber optic cable (8) is much shorter than the length of the first fiber optic depolarization and delay line (9); the lengths of the third sensing optical cable (12) and the fourth sensing optical cable (13) are far shorter than the lengths of the second optical fiber depolarization and delay line (14); … …, and so on, the lengths of the 2n-1 sensing fiber optic cable (16) and the 2n sensing fiber optic cable (17) are each much shorter than the length of the n optical fiber depolarization and delay line 18.
7. The quasi-distributed vibration alarm fiber system based on coarse wavelength division multiplexing according to claim 1, wherein the n-1 three-port coarse wavelength division multiplexers (5), (10), … … are formed in the form of micro-optic collimating mirrors and interference filters.
8. A quasi-distributed vibration alarm optical fiber system based on coarse wavelength division multiplexing according to claim 1, wherein the 1*n coarse wavelength division multiplexer (3) adopts AWG structure, and each optical path output band corresponds to the reflection spectrum of each three-port coarse wavelength division multiplexer.
9. The quasi-distributed vibration alarm optical fiber system based on coarse wavelength division multiplexing according to claim 1, wherein the ultra-wide spectrum light source (1) has an ultra-radiation light source with a width of tens of nm, and a semiconductor laser is adopted to pump an active optical fiber to generate wide-spectrum fluorescence, and ultra-wide spectrum light output is obtained through an isolator and a special filter; the ultra-wide spectrum light source (1) adopts a semiconductor super-radiation diode for output.
CN202311509236.3A 2023-11-14 2023-11-14 Quasi-distributed vibration alarm optical fiber system based on coarse wavelength division multiplexing Pending CN117975636A (en)

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