CN114252246A - Optical fiber testing method and system - Google Patents
Optical fiber testing method and system Download PDFInfo
- Publication number
- CN114252246A CN114252246A CN202111679971.XA CN202111679971A CN114252246A CN 114252246 A CN114252246 A CN 114252246A CN 202111679971 A CN202111679971 A CN 202111679971A CN 114252246 A CN114252246 A CN 114252246A
- Authority
- CN
- China
- Prior art keywords
- optical fiber
- test
- output
- mode
- fiber
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000013307 optical fiber Substances 0.000 title claims abstract description 100
- 238000012360 testing method Methods 0.000 title claims abstract description 61
- 238000000034 method Methods 0.000 claims abstract description 11
- 238000012544 monitoring process Methods 0.000 claims abstract description 4
- 239000000835 fiber Substances 0.000 claims description 30
- 238000005253 cladding Methods 0.000 claims description 10
- 230000003287 optical effect Effects 0.000 claims description 8
- 229910052761 rare earth metal Inorganic materials 0.000 claims description 4
- 229910052769 Ytterbium Inorganic materials 0.000 claims description 3
- 238000012545 processing Methods 0.000 claims description 3
- NAWDYIZEMPQZHO-UHFFFAOYSA-N ytterbium Chemical compound [Yb] NAWDYIZEMPQZHO-UHFFFAOYSA-N 0.000 claims description 3
- 238000007405 data analysis Methods 0.000 claims description 2
- 230000004927 fusion Effects 0.000 claims 1
- 238000010998 test method Methods 0.000 claims 1
- 238000005516 engineering process Methods 0.000 abstract description 3
- 238000004519 manufacturing process Methods 0.000 description 4
- 238000004458 analytical method Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 150000002910 rare earth metals Chemical class 0.000 description 2
- 230000001960 triggered effect Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000012792 core layer Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 239000005368 silicate glass Substances 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
- G01M11/02—Testing optical properties
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
- G01M11/30—Testing of optical devices, constituted by fibre optics or optical waveguides
Landscapes
- Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Lasers (AREA)
Abstract
A method and system for testing optical fiber, the method of the present invention includes: establishing an optical fiber amplifier system for detecting the performance of an optical fiber, testing a mode instability threshold p1 of the optical fiber, then setting the output power of the optical fiber amplifier to be p1 xA, copying to test light emission, wherein A is only used as a parameter and has no physical significance, meanwhile, A is set to be 93-97%, recording light emission time and monitoring whether a mode instability phenomenon occurs or not, finally, recording and analyzing data, stopping light emission when the mode is unstable, and recording light emission time as t; if t is larger than the preset threshold value, the optical fiber is qualified, and if t is smaller than the preset threshold value, the optical fiber is unqualified. The method is used for solving the problems of long time consumption, large workload and low efficiency of the existing optical fiber testing technology.
Description
Technical Field
The invention relates to the technical field of optical fiber detection, in particular to an optical fiber testing method and an optical fiber testing system.
Background
In order to improve the light-emitting quality, the service life and the working stability of the laser, the physical properties of the gain fiber in the laser need to be tested and screened in the production process of the fiber laser. For industrial high power fiber lasers, the main physical problems include photodarkening and Transverse Mode Instability (TMI).
Photodarkening refers to the phenomenon that the background loss of a doped fiber core layer is permanently increased after a fiber laser emits light for a long time, and the phenomenon generally exists in rare earth doped silicate glass, particularly in ytterbium-doped high-power fiber lasers. With the increase of the light emitting time of the laser, the output power gradually decreases and finally tends to be stable, and the power decreases by more than 20% after the light is emitted for a long time. Industrial high power fiber lasers typically require a quality guarantee period of more than one year, which requires that the fiber lasers still achieve stable power output after long-term operation, and therefore, industrial fiber lasers typically need to retain a certain power redundancy to offset the power reduction caused by photon darkening.
The TMI is a phenomenon that after the output power of laser reaches a certain threshold, the fundamental mode in the fiber core starts to be nonlinearly coupled with the high-order mode, the output laser power jumps back and forth between the fundamental mode and the high-order mode, and the beam quality is degraded sharply. TMI will cause the laser focal spot to change rapidly, causing laser processing quality to be unstable, so industrial lasers must suppress TMI.
Photon darkening and TMI are different physical phenomena, but have close internal correlation, and the photon darkening phenomenon can increase the background loss of the optical fiber, so that the optical fiber absorbs signal light, and the thermal load of the optical fiber is improved; the thermal load is increased, so that the thermally induced long-period refractive index grating in the fiber core is further strengthened, and the TMI threshold value is reduced; therefore, when the optical fiber laser generates photon darkening, the TMI can be triggered simultaneously, so that the photon darkening and the TMT change the heat load in the optical fiber, thereby influencing the output power.
The existing optical fiber testing technology is to put a testing optical fiber into an optical fiber amplifier as a gain optical fiber, then use a broad spectrum laser as a seed light source of the optical fiber amplifier, then start the laser to continuously emit light for a long time, simultaneously set a data acquisition system at the laser output port of the optical fiber amplifier, monitor the power of the output laser of the laser, record the curve (P-t curve) of the output power changing with time, and judge whether the optical fiber is qualified by observing whether the P-t has obvious power reduction. The testing technology usually takes about 500 hours, and is long in time and large in workload.
Disclosure of Invention
The technical problem to be solved by the invention is to provide an optical fiber testing method and system which can shorten the detection time of a gain optical fiber, improve the testing efficiency and improve the production efficiency of a laser.
The technical scheme adopted for solving the technical problems is as follows:
the invention relates to a method for testing an optical fiber, which comprises the following steps:
s1: establishing an optical fiber amplifier system for detecting the performance of the optical fiber;
s2: setting a preset threshold, placing a test optical fiber in an optical fiber amplifier system, firstly testing a mode instability threshold p1 of the optical fiber, then setting the output power of the optical fiber amplifier to be p1 xA, and then performing copying test to emit light, wherein A is a coefficient and has no physical significance; meanwhile, setting A to be 93-97%, recording light emitting time and monitoring whether a mode instability phenomenon occurs or not; criterion whether mode instability occurs: the standard deviation (STD) of the output power is analyzed by recording the curve of the output power changing along with the time, and when the STD exceeds 0.01, the mode is considered to be unstable;
s3: data analysis, stopping light emission when the mode is unstable, and recording the light emission time as t; if t is larger than the preset threshold value, the optical fiber is qualified, and if t is smaller than the preset threshold value, the optical fiber is unqualified.
Further, the preset threshold is 12-24 hours.
The invention relates to an optical fiber testing system, which is sequentially connected with a seed source laser, an optical fiber amplifier, a data acquisition system and a testing optical fiber arranged in the optical fiber amplifier from left to right; a pump source, a beam combiner, a cladding light power filter and a QBH output head are sequentially arranged in the optical fiber amplifier, the output end of the pump source is welded with the input end of the beam combiner, a test optical fiber is connected between the beam combiner and the cladding light power filter, the input end of the beam combiner is connected with the output end of a seed source laser, and the QBH output head is connected with a data acquisition system; the data acquisition system comprises a photoelectric sensor for converting optical signals into electric signals, a data acquisition card for processing and feeding back the electric signals, and a computer for recording output data.
Further, the output end of the beam combiner is connected with one end of the test optical fiber, and the other end of the test optical fiber is connected with the output end of the cladding optical power filter.
Further, the test fiber is a rare earth element doped fiber, preferably an ytterbium doped fiber.
In the prior art, mode instability is usually taken as a defect of a fiber laser, the invention provides a method and a system for testing an optical fiber, which utilize the phenomenon of mode instability, and are used for testing the optical fiber, if the photon darkening resistance of the tested optical fiber can not meet the requirement of preparing a laser, the mode instability phenomenon can be triggered in a short time when a baking machine is tested near a mode instability threshold value, so that the testing time is greatly shortened.
Compared with the prior art, the invention has the beneficial effects that:
the method of the invention has the advantages of short test time, high test efficiency and high laser production efficiency, the copying is carried out near the unstable threshold value of the optical fiber mode, if the photon darkening resistance performance of the optical fiber does not meet the requirement, the mode instability phenomenon can be generated due to photon darkening in a short time, and the test time can be shortened to 1h at least. Tests show that by adopting the testing method disclosed by the invention, if the tested optical fiber is unqualified under the specified output power, the copying time is about 12-24 h at most, and the phenomenon of mode instability can occur, so that the unqualified optical fiber to be tested is judged, the testing time is greatly shortened, the testing efficiency is improved, and the overall production efficiency of the laser is improved.
Drawings
FIG. 1 is a schematic diagram of a system configuration according to an embodiment of the present invention;
FIG. 2 is a graph of power measurements taken from a qualified optical fiber in accordance with an embodiment of the present invention;
FIG. 3 is a graph illustrating power measurements taken with a defective fiber in accordance with an embodiment of the present invention.
In the figure: 1. the device comprises a seed source laser, 2. an optical fiber amplifier, 3. a data acquisition system, 4. a pumping source, 5. a beam combiner, 6. a test optical fiber, 7. a cladding light power filter and 8. a QBH output head.
Detailed Description
The invention is further described below with reference to the accompanying drawings and examples, the method comprising the steps of:
s1, establishing an optical fiber amplifier system for detecting the performance of the optical fiber; the optical fiber amplifier system is connected with a computer to realize the feedback of the test value;
s2, setting a preset threshold, placing the test optical fiber in an optical fiber amplifier system, firstly testing the mode instability threshold p1 of the optical fiber, then setting the output power of the optical fiber amplifier to p1 xA, and then performing copying test to emit light, wherein A is a coefficient and has no physical significance; meanwhile, setting A to be 93-97%, recording light emitting time and monitoring whether a mode instability phenomenon occurs or not; criterion whether mode instability occurs: the standard deviation (STD) of the output power is analyzed by recording the curve of the output power changing along with the time, and when the STD exceeds 0.01, the mode is considered to be unstable;
s3, analyzing data, stopping light emitting when the mode is unstable, and recording the light emitting time as t; if t is larger than the preset threshold value, the optical fiber is qualified, and if t is smaller than the preset threshold value, the optical fiber is unqualified.
The optical fiber amplifier system in S1 comprises a seed source laser 1, an optical fiber amplifier 2 and a data acquisition system 3 which are connected in sequence from left to right, wherein the output end of the seed source laser 1 is connected with the input end of the optical fiber amplifier 2, the inside of the optical fiber amplifier 2 is connected with a pump source 4, a beam combiner 5, a cladding optical power filter 7 and a QBH output head 8 in sequence, the output end of the pump source 4 is welded with the input end of the beam combiner 5, the input end of the beam combiner 5 is connected with the output end of the seed source laser 1, the output end of the beam combiner 5 is connected with one end of a test optical fiber 6, the other end of the test optical fiber 6 is connected with the input end of the cladding optical power filter 7, the output end of the cladding optical power filter 7 is connected with the QBH output head 8 to form the optical fiber amplifier 2, the test optical fiber 6 is directly tested in the optical fiber amplifier 2, the output end of the QBH output head 8 is connected with the data acquisition system 3, the test data of the test optical fiber 6 is transmitted into the data acquisition system 3, further, in order to facilitate the feedback and analysis of the data, the data acquisition system 3 comprises a photoelectric sensor, a data acquisition board card and a computer, the photoelectric sensor is directly connected with the QBH output head 8, so that the collected optical signal is converted into an electric signal through the photoelectric sensor, then the electric signal of the photoelectric sensor is transmitted into the data acquisition board card, the electric signal of the photoelectric sensor is processed, then the data is fed back to the computer end, the data is collected and recorded at regular time through the computer end, and the P-t curve of the test optical fiber 6 is input, so that the standard deviation (STD) of the output power is analyzed through analyzing the P-t curve, and when the standard deviation exceeds 0.01, the mode is considered to be unstable. For example, after a period of time t, the standard deviation STD of the output power is greater than 0.01, which indicates that the mode is unstable, and if t meets the preset condition, it can be determined that the measured optical fiber is qualified; otherwise, the tested optical fiber can be judged to be unqualified.
To ensure a high brightness output, the test fiber 6 is a rare earth doped fiber, preferably an ytterbium doped fiber.
For better analysis of the output power variation of the test fiber 6, the output power of the fiber amplifier 2 with the test fiber 6 as a gain fiber was set to 4kW, and the mode instability threshold was 4.21 kW. When the output power of an optical fiber amplifier taking a measured optical fiber as a gain optical fiber is 4kW, copying is carried out for 12-24 h, and if the mode instability phenomenon does not occur, the optical fiber can be judged to be used for preparing a laser with the power higher than 4 kW.
Referring to fig. 2, for the test of a qualified optical fiber, after 500 hours of copying is required, the existing method determines that the optical fiber is qualified after no obvious output power reduction is confirmed; in this embodiment, the optical fiber is determined to be qualified by performing the baking at the preset power, and when the standard deviation STD of the output power reaches above 0.01, the mode is considered to be unstable, the light emitting time t for which the mode is unstable is 47h, and is greater than the preset threshold, and the test time is shortened to about 1/10 by applying the test optical fiber 6 to the system of the method.
Referring to fig. 3, for the test of the failed optical fiber, the conventional method needs at least 300 h to start the output power reduction caused by the photodarkening, so as to judge that the optical fiber is failed. In this embodiment, the baking is performed at the preset power for 5 hours, and at this time, the standard deviation STD of the output power reaches above 0.01, it is determined that the mode is unstable, the light emitting time t is less than the preset threshold, it can be determined that the optical fiber is unqualified, and the test time is greatly shortened.
Claims (7)
1. A method of testing an optical fiber, comprising the steps of:
s1, establishing an optical fiber amplifier system for detecting the performance of the optical fiber;
s2, setting a preset threshold, placing the test optical fiber in the optical fiber amplifier system, firstly testing the mode instability threshold p1 of the optical fiber, then setting the output power of the optical fiber amplifier to p1 xA, and then performing copying test to emit light, wherein A is a coefficient and has no physical significance; meanwhile, setting A to be 93-97%, recording light emitting time and monitoring whether a mode instability phenomenon occurs or not;
s3: data analysis, stopping light emission when the mode is unstable, and recording the light emission time as t; if t is larger than the preset threshold value, the optical fiber is qualified, and if t is smaller than the preset threshold value, the optical fiber is unqualified.
2. The method of claim 1, wherein in S2, the criterion of the mode instability phenomenon is: the standard deviation STD of the output power is analyzed by recording the curve of the output power changing along with time, and when the STD exceeds 0.01, the mode is considered to be unstable.
3. The method according to claim 1 or 2, wherein the preset threshold is 12-24 h.
4. A system for optical fiber testing, comprising: a seed source laser (1), an optical fiber amplifier (2), a data acquisition system (3) and a test optical fiber (6) placed in the optical fiber amplifier (1) are sequentially connected from left to right; be equipped with pump source (4), beam combiner (5), cladding light power filter ware (7) and QBH delivery head (8) in proper order in fiber amplifier (2), the output of pump source (4) and the input butt fusion of beam combiner (5), be connected with test fiber (6) between beam combiner (5) and cladding light power filter ware (7), the input and the seed source laser instrument (1) output of beam combiner (5) are connected, QBH delivery head (8) are connected with data acquisition system (3).
5. The system according to claim 4, characterized in that the data acquisition system (3) comprises a photoelectric sensor for converting optical signals into electrical signals, a data acquisition card for processing and feeding back the electrical signals, and a computer for recording output data.
6. The system according to claim 4 or 5, characterized in that the output of the combiner (5) is connected to one end of a test fiber (6), and the other end of the test fiber (6) is connected to the output of a cladding optical power filter (7).
7. System according to claim 6, characterized in that the test fiber (6) is a rare earth element doped fiber, preferably an ytterbium doped fiber.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111679971.XA CN114252246A (en) | 2021-12-31 | 2021-12-31 | Optical fiber testing method and system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111679971.XA CN114252246A (en) | 2021-12-31 | 2021-12-31 | Optical fiber testing method and system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114252246A true CN114252246A (en) | 2022-03-29 |
Family
ID=80799169
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111679971.XA Pending CN114252246A (en) | 2021-12-31 | 2021-12-31 | Optical fiber testing method and system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114252246A (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5619321A (en) * | 1995-04-13 | 1997-04-08 | Cselt -Centro Studi E Laboratori Telecommunicazioni S.P.A. | Method of and device for measuring the Kerr non-linearity coefficient in a single mode optical fiber |
| CN103684606A (en) * | 2013-12-12 | 2014-03-26 | 武汉光迅科技股份有限公司 | System and method for improving dynamic working performance of optical fiber amplifier |
| CN106226035A (en) * | 2016-07-25 | 2016-12-14 | 长飞光纤光缆股份有限公司 | A kind of Yb dosed optical fiber photon darkens test system |
| CN109323850A (en) * | 2018-10-29 | 2019-02-12 | 大族激光科技产业集团股份有限公司 | Optical fiber laser scatters light detection device and laser power calibration and feedback method |
| CN113567089A (en) * | 2021-09-23 | 2021-10-29 | 武汉锐科光纤激光技术股份有限公司 | Double-cladding active optical fiber automatic testing device and method for optical fiber laser |
-
2021
- 2021-12-31 CN CN202111679971.XA patent/CN114252246A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5619321A (en) * | 1995-04-13 | 1997-04-08 | Cselt -Centro Studi E Laboratori Telecommunicazioni S.P.A. | Method of and device for measuring the Kerr non-linearity coefficient in a single mode optical fiber |
| CN103684606A (en) * | 2013-12-12 | 2014-03-26 | 武汉光迅科技股份有限公司 | System and method for improving dynamic working performance of optical fiber amplifier |
| CN106226035A (en) * | 2016-07-25 | 2016-12-14 | 长飞光纤光缆股份有限公司 | A kind of Yb dosed optical fiber photon darkens test system |
| CN109323850A (en) * | 2018-10-29 | 2019-02-12 | 大族激光科技产业集团股份有限公司 | Optical fiber laser scatters light detection device and laser power calibration and feedback method |
| CN113567089A (en) * | 2021-09-23 | 2021-10-29 | 武汉锐科光纤激光技术股份有限公司 | Double-cladding active optical fiber automatic testing device and method for optical fiber laser |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Koponen et al. | Photodarkening in ytterbium-doped silica fibers | |
| CA2657790C (en) | Fiber laser for ultrasonic laser testing | |
| CN113504032B (en) | Fiber grating test system and method | |
| CN102565016B (en) | Detected temperature effect compensation device and method based on fluorescent quenching sensor | |
| CN111006848B (en) | Optical darkening testing device and method for ytterbium-doped quartz optical fiber with all-fiber structure | |
| CN110987368A (en) | Optical darkening test device and method for ytterbium-doped quartz optical fiber | |
| CN108225745A (en) | A kind of Double Cladding Ytterbium Doped Fiber laser slope efficiency test system and test method | |
| CN113203548A (en) | Device and method for testing loss of double-clad optical fiber core | |
| CN110095258B (en) | Device and method for measuring energy level life of rare earth ions in active optical fiber | |
| CN114252246A (en) | Optical fiber testing method and system | |
| CN115077864A (en) | Return light testing system and method based on fiber laser | |
| US20040190123A1 (en) | Optical transmission apparatus | |
| US9356418B2 (en) | All fiber low dynamic pointing high power LMA fiber amplifier | |
| CN113155795B (en) | Device and method for directly measuring upper energy level fluorescence lifetime of rare earth element doped optical fiber laser | |
| CN1756133A (en) | Quality control of optical fiber amplfier | |
| CN104028891B (en) | Welding system for online monitoring laser crystal strain and online monitoring method thereof | |
| CN212963955U (en) | Optical fiber mode gain measuring device | |
| Chen et al. | Photodarkening-induced absorption and fluorescence changes in Yb fibers | |
| CN104028919A (en) | Welding system for online monitoring laser crystal transmittance and online monitoring method thereof | |
| CN105552703A (en) | Method and device for adjusting output energy of laser amplifier | |
| CN106654831A (en) | Laser having self-test function and self-test method of laser | |
| CN116222971A (en) | Fluorescent lifetime detection device and method for optical fiber preform | |
| CN221260346U (en) | Testing device for measuring absorption efficiency of gain optical fiber pump light | |
| CN101762343B (en) | Method for measuring temperature of optical fiber core | |
| CN221826430U (en) | Ytterbium-doped optical fiber photon darkening testing device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20220329 |
|
| RJ01 | Rejection of invention patent application after publication |