CN210180640U

CN210180640U - An abnormality detection system in an optical fiber

Info

Publication number: CN210180640U
Application number: CN201921434861.5U
Authority: CN
Inventors: Hang Zhang; 张航; Rongrong Qi; 戚蓉蓉; Yuejiao Hu; 胡月胶; Jiawen Chen; 陈嘉文; Huiling Ma; 马慧玲; Yong Li; 李勇
Original assignee: Zhejiang University of Technology ZJUT
Current assignee: Zhejiang University of Technology ZJUT
Priority date: 2019-08-31
Filing date: 2019-08-31
Publication date: 2020-03-24
Anticipated expiration: 2029-08-31

Abstract

The utility model discloses an unusual detecting system in optic fibre, including optic fibre, coupling lens, reverse device, fluorescence cap and photoelectric detector of assembling, coupling lens sets up in the optical fiber coupling end to connect laser source and optic fibre through coupling lens, fluorescence cap sets up in the optic fibre illumination end, and the white light that fluorescence cap arouses is along optic fibre reverse transmission, reverse device setting of assembling is in the optical fiber coupling end for detect on assembling photoelectric detector with reverse transmission signal light. The utility model has the advantages that: the double-clad optical fiber is adopted, the fiber core is used for transmitting energy, the inner cladding transmits signals, the fiber core does not absorb signal light, and the signal light transmitted by the inner cladding is used for detecting whether the fiber core breaks down or not, so that the illumination safety is guaranteed, and the utilization rate of the optical fiber is improved.

Description

Optical fiber internal anomaly detection system

Technical Field

The utility model relates to a laser leaded light illumination and the flexible processing field of laser, concretely relates to unusual detecting system in optic fibre.

Background

In the optical fiber light guide illumination, the light flux of watt level needs to be coupled into the optical fiber, the optical fiber is an important means for realizing flexible transmission, and the optical fiber can avoid the limitation of refraction-reflection light path, so that the path is more flexible; but powerful transmission makes the energy density in the optical fiber cross-section very high, if the optic fibre defect or fracture arouse accidents such as burning easily, therefore the fault detection of optic fibre is very important, the utility model provides an unusual detecting means in the optic fibre solves this type of technical problem.

SUMMERY OF THE UTILITY MODEL

To the problem that exists among the prior art, the utility model provides an anomaly detection system in optic fibre rational in infrastructure.

The technical scheme of the utility model as follows:

the utility model provides an unusual detecting system in optic fibre, its characterized in that includes laser light source, coupling lens, optic fibre, fluorescence cap, reverse device, band pass filter and photoelectric detector that assembles, coupling lens sets up the coupling end at optic fibre, optic fibre passes through the external laser light source of coupling lens, fluorescence cap sets up the illumination end at optic fibre for reverse excitation signal light carries out reverse transmission with signal light along optic fibre, reverse device setting that assembles is in the coupling end of optic fibre for on assembling band pass filter with reverse transmission's signal light, detect through photoelectric detector.

The system for detecting the abnormality in the optical fiber is characterized in that the optical fiber adopts a step-index double-clad optical fiber and comprises a fiber core, a first cladding and a second cladding, wherein the fiber core is used for transmitting energy, the first cladding is used for transmitting signals, and the second cladding is used for limiting signal light to be transmitted in the first cladding.

The system for detecting the abnormality in the optical fiber is characterized in that the optical fiber adopts a step-index single-cladding optical fiber or a graded-index optical fiber and comprises a fiber core and a first cladding, wherein the fiber core is used for channel multiplexing and can transmit energy and signals, and the graded-index optical fiber has the largest central refractive index of the fiber core and is gradually reduced along the radial direction.

The system for detecting the abnormality in the optical fiber is characterized in that the reverse converging device adopts a reverse converging lens which is nested on the coupling lens.

The system for detecting the abnormality in the optical fiber is characterized in that the reverse convergence device is provided with an oblique wedge at the optical fiber coupling end, so that reverse transmission signal light is reflected to the photoelectric detector through the oblique wedge.

The system for detecting the abnormality in the optical fiber is characterized in that the refractive index of the second cladding is smaller than that of the first cladding, and the refractive index of the first cladding is smaller than that of the fiber core.

The utility model has the advantages that: the double-clad optical fiber is adopted, the fiber core is used for transmitting energy, the inner cladding transmits signals, the fiber core does not absorb signal light, and the signal light transmitted by the inner cladding is used for detecting whether the fiber core breaks down or not, so that the illumination safety is guaranteed, and the utilization rate of the optical fiber is improved.

Drawings

FIG. 1 is a schematic view of a total reflection type meridian reflection signal light of the present invention;

fig. 2 is a schematic diagram of an oblique ray spiral type reflected signal light of the present invention;

FIG. 3 is a schematic view of the wedge structure of the present invention;

in the figure: the optical fiber coupling device comprises a laser light source 1, a coupling lens 2, an optical fiber 3, a fiber core 31, a first cladding 32, a second cladding 33, a fluorescent cap 4, a reverse converging lens 5, a band-pass filter 6 and a photoelectric detector 7.

Detailed Description

The invention is further described with reference to the accompanying drawings.

As shown in fig. 1-3, an optical fiber internal abnormality detection system includes a laser light source 1, a coupling lens 2, an optical fiber 3, a fluorescent cap 4, a reverse converging device, a band-pass filter 6, and a photodetector 7.

The laser light source 1 is a blue laser light source with the wavelength of 450 nm; including but not limited to: semiconductor lasers, solid state lasers, gas lasers, fiber lasers, and the like.

The coupling lens 2 adopts an imaging optical lens or a lens group and a non-imaging optical free-form surface lens; a non-imaging optical free-form surface lens is preferably used for coupling the light emitted by the laser light source 1 for illumination into the fiber core of the optical fiber;

the optical fiber 3 is a novel optical fiber for channel multiplexing, and the optical fiber can adopt a step-index double-clad optical fiber, a step-index single-clad optical fiber or a graded-index optical fiber; the graded index optical fiber comprises a fiber core 31 and a first cladding 32, wherein the fiber core 31 can transmit energy and signals through channel multiplexing, and the refractive index of the graded index optical fiber is highest in the center and gradually decreases along the radial direction. The preferred double-clad fiber with step index of the present invention comprises a fiber core 31, a first cladding 32 (inner cladding) and a second cladding 33 (outer cladding), wherein the fiber core 31 is used for transmitting energy, the inner cladding is used for transmitting signals, the outer cladding is used for limiting signal light to be transmitted in the inner cladding, and the fiber core 31 satisfies that the fiber core does not absorb the signal light transmitted in the inner cladding; the fiber core 31 can also be used for transmitting signals, the inner cladding is used for transmitting energy, the outer cladding is used for limiting energy transmission light to be transmitted in the inner cladding, and the fiber core 31 meets the condition that the fiber core does not absorb the energy light transmitted in the inner cladding; wherein the inner cladding and the fiber core form a multimode waveguide, and the outer cladding and the inner cladding also form a multimode waveguide; the step-index double-clad fiber has an outer cladding smaller than the inner cladding, and an inner cladding smaller than the fiber core. The light transmitted by the inner cladding comprises two modes of meridional light full-emission transmission and oblique light spiral advancing.

1. Satisfies the condition that the incident angle is less than or equal to

The meridional rays of light can be transmitted by total reflection in the optical fiber,

；

2. satisfies the condition that the incident angle is less than or equal to

The oblique light rays of (a) may be helically transmitted in the optical fiber,

，

(ii) a Wherein 𝜑 is the angle between the oblique ray and the radial direction of the end face of the optical fiber, gamma is the angle between the oblique ray and the projection of the oblique ray on the section of the optical fiber, and n₁And n₂Is the refractive index of the core and the inner cladding, n₀Is the refractive index of the outer cladding.

The fluorescent cap 4 is a device for converting blue light into white light, and the fluorescent cap itself has a property of bidirectional excitation, so that white signal light transmitted back in the reverse direction is transmitted to the coupling end in the reverse direction in the first cladding layer in a portion satisfying the aperture of the first cladding layer numerical value.

The reverse converging lens 5 is used for converging the white light which is transmitted back in the reverse direction to the filter 6, the reverse converging lens 5 does not influence a forward light path, can be nested on the coupling lens 2 when the intensity of the white light which is transmitted in the reverse direction is enough, and can also make an inner cladding layer and an outer cladding layer of an optical fiber end surface into an oblique-wedge type at the coupling end, and an oblique-wedge structure is added between the optical fiber end surface or the inner cladding layer and the outer cladding layer, and the oblique-wedge type is reflected to the photoelectric detector 7 for detection (such as the left end position shown in fig. 3.

The band-pass filter 6 is used for filtering the influence of the light collected by the convergent lens and the blue light of the coupling end, the photoelectric detector 7 is a photodetector for judging whether the optical fiber has a fault, and the damage of the optical fiber can not detect the white light or the white light is obviously reduced.

In the optical fiber internal anomaly detection system, light emitted by a laser light source 1 is coupled into a fiber core 31 of an optical fiber after passing through a coupling lens 2 and is transmitted through the optical fiber 3, a fluorescent cap 4 is used for converting blue light into white light, and the blue light is filtered through a filter 6 after being collected through a reverse converging lens, so that the influence of the blue light is eliminated, and finally whether the optical fiber breaks down or not is detected through a photoelectric detector 7.

Anomalies within the fiber optic fibers of the present system include, but are not limited to: breaking the optical fiber; optical fiber burn-in caused by hole burning, flaw and end surface pollution caused by internal defects of the optical fiber; quality degradation, etc.

Claims

1. An abnormality detection system in an optical fiber, characterized in that it comprises a laser light source (1), a coupling lens (2), an optical fiber (3), a fluorescent cap (4), a reverse convergence device, a filter (6) and A photodetector (7), the coupling lens (2) is arranged at the coupling end of the optical fiber (3), and the optical fiber (3) is externally connected to the laser light source (1) through the coupling lens (2); the fluorescent cap (4) It is arranged at the lighting end of the optical fiber (3), and is used to reversely excite the signal light and transmit the signal light in the reverse direction along the optical fiber (3). The signal light transmitted in the opposite direction is collected on the band-pass filter (6), and detected by the photodetector (7).

2. The system for detecting anomalies in an optical fiber according to claim 1, wherein the optical fiber (3) adopts a step-index double-clad optical fiber, comprising a core (31), a first cladding ( 32) and the second cladding (33), wherein the core (31) is used to transmit energy, the first cladding (32) is used to transmit signals, and the second cladding (33) is used to confine the signal light to the first transmitted in the cladding (32).

3. An abnormality detection system in an optical fiber according to claim 1, characterized in that the optical fiber (3) adopts a step-index single-clad optical fiber or a graded-index optical fiber, comprising a core (31) and a The first cladding (32), in which the fiber core (31) is channel multiplexing, transmits both energy and signal.

4. An abnormality detection system in an optical fiber according to claim 1, characterized in that the reverse convergence device adopts a reverse convergence lens (5), and the reverse convergence lens (5) is nested in the coupling on the lens (2).

5 . The abnormality detection system in an optical fiber according to claim 1 , wherein the reverse convergence device adopts an oblique split at the optical fiber coupling end, so that the reverse transmission signal light is reflected to the photoelectric detection through the oblique split. 6 . on the device (7).

6. An optical fiber abnormality detection system according to claim 2, characterized in that, the refractive index of the second cladding layer (33) is smaller than the refractive index of the first cladding layer (32), and the first cladding layer The refractive index of (32) is less than that of the core (31).