CN112033574A - Distributed fiber laser monitoring system and monitoring method - Google Patents
Distributed fiber laser monitoring system and monitoring method Download PDFInfo
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- CN112033574A CN112033574A CN202011048317.4A CN202011048317A CN112033574A CN 112033574 A CN112033574 A CN 112033574A CN 202011048317 A CN202011048317 A CN 202011048317A CN 112033574 A CN112033574 A CN 112033574A
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- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K11/00—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00
- G01K11/32—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 using changes in transmittance, scattering or luminescence in optical fibres
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Abstract
The invention discloses a distributed fiber laser monitoring system and a distributed fiber laser monitoring method. The invention uses the sensing optical fiber/optical cable of the Raman scattering technology as the sensor, thereby only needing one optical fiber to realize the real-time temperature monitoring of the whole optical fiber laser, and accurately obtaining the information of any point on the sensing optical fiber, and solving the problem of missing detection of the point sensor. In addition, the communication optical fiber is adopted as the sensor, so that the cost of the sensor is greatly reduced.
Description
Technical Field
The invention relates to a safety monitoring and protecting technology of a fiber laser system, in particular to a distributed fiber laser monitoring system and a monitoring method.
Background
The high-power optical fiber laser is a mainstream tool for applications such as metal plate cutting, metal welding, additive manufacturing and the like, and is an important supporting unit for modern industrial 4.0 and intelligent manufacturing. However, the high-power fiber laser light source is a double-edged sword, and can realize the processing of a high-energy-density metal block, but once faults occur, such as the rise of light leakage temperature of the optical fiber, heat accumulation caused by nonlinear effect, heating caused by melting point loss, and serious self-damage and even the whole laser system can be burnt under the conditions of gain extrusion and energy transmission of the optical fiber. The development of high power fiber laser technology has also been struggling with waste heat (strong laser and particle beam 32(1)2020), and monitoring the safe operating state of high power fiber lasers is crucial for laser applications. The safety parameters in the current high-power optical fiber laser are mostly related to heat/temperature.
At present, point type detectors and sensors are adopted for self-safety protection in a high-power optical fiber laser system and are used for self-checking and detecting the operation state of each position in the system in real time. The most applied are Photo Detectors (PD) and Temperature sensors (Temperature sensors), wherein the photo detectors mainly function to collect the dim light signals of the fiber leakage at the measured point to characterize the laser power at the point. The temperature sensor is mainly used for detecting the temperature condition of a measured point and judging whether the device/optical fiber/pumping laser/circuit board at the key position normally operates or not. Such as patents CN107219063A, CN105562952A, CN105914568A, CN 103904532B. Utility model CN205070149U, CN204142995U, CN205961125U, CN206378272U all adopt point type photoelectric detector and sensor as detecting element, and a detector can only survey the signal of a certain point, and the application of actual high power fiber laser system needs a plurality of combinations to carry out signal detection one by one.
The point type sensor needs each sensor to be connected with a wire, each circuit of sensor needs to be connected with a circuit board, and the work of signal acquisition, signal demodulation, signal uploading, signal processing feedback and the like needs to be carried out on the circuit board. Some regional signals are weak, and special amplifying circuits need to be manufactured for the sensors, so that the workload is large, and the cost is increased. At present, the number of sensors of a 1kW fiber laser module is 5-10, and the number of sensors of a ten-kilowatt-level high-power multimode fiber laser system is hundreds, so that background fault location is difficult to realize in practical application, and faults without sensor point positions are difficult to find.
Disclosure of Invention
The invention aims to provide a distributed fiber laser monitoring system capable of realizing continuous distributed temperature monitoring.
Another object of the present invention is to provide a distributed fiber laser monitoring method.
The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.
According to an aspect of the present invention, a distributed fiber laser monitoring system is provided, which includes a fiber laser and a sensor, where the sensor is a sensing fiber or a sensing cable, and the sensor performs continuous distributed real-time monitoring on a temperature parameter in the fiber laser by using a raman scattering technique.
In an embodiment, the fiber laser of the distributed fiber laser monitoring system is a kilowatt-level and above high-power single-mode fiber laser or a high-power multimode fiber laser composed of a plurality of kilowatt-level single-mode fiber laser modules.
In one embodiment, the response time of the sensor of the distributed fiber laser monitoring system is within 1s, the temperature resolution is within 0.1 ℃, and the temperature measurement precision is within 1 ℃.
In one embodiment, the monitoring area of the sensor of the distributed fiber laser monitoring system comprises a semiconductor laser of the fiber laser, a gain fiber, a fiber device, a monitoring circuit board, a laser power supply and an output head.
In one embodiment, the sensor of the distributed fiber laser monitoring system employs an intrinsically safe passive fiber.
In an embodiment, the sensor of the distributed fiber laser monitoring system includes a positioning function, the positioning function adopts an optical time domain reflection technology, and the positioning accuracy is within 0.1 m.
In an embodiment, the test beam and the temperature monitoring sensing beam of the optical time domain reflection technique of the distributed fiber laser monitoring system are the same pulse laser.
In one embodiment, when the fiber laser is a high-power multimode fiber laser, the distributed fiber laser monitoring system is provided with a sheath between the modules exposed outside the sensor.
In one embodiment, the external sensors between the modules of the distributed fiber laser monitoring system are connected through cold flanges by AC/PC joints.
According to another aspect of the present invention, a distributed fiber laser monitoring method is further provided, in which a sensing fiber or a sensing optical cable is used as a sensor, and a raman scattering technique is used to perform continuous distributed real-time monitoring on the temperature in the fiber laser.
The system and the method have the advantages that: by using the sensing optical fiber/optical cable of the Raman scattering technology as the sensor, distributed real-time temperature monitoring can be realized only by one optical fiber, information of any point on the sensing optical fiber can be accurately obtained, and the problem that the point sensor leaks detection is solved. In addition, the communication optical fiber is adopted as the sensing unit, so that the cost of the sensor is greatly reduced.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.
The above features and advantages of the present disclosure will be better understood upon reading the detailed description of embodiments of the disclosure in conjunction with the following drawings. In the drawings, components are not necessarily drawn to scale, and components having similar relative characteristics or features may have the same or similar reference numerals.
Fig. 1 is a schematic diagram of an internal structure of a conventional single-module fiber laser;
FIG. 2 is a schematic diagram of the placement of the sensing fiber of the present invention inside a single module fiber laser;
FIG. 3 is a schematic diagram of a sensing fiber shared by high-power multimode fiber lasers according to the present invention;
wherein: 1-a semiconductor laser; 2-an optical fiber device; a 3-gain optical fiber; 4-monitoring the circuit board; 5-sensing optical fiber; 6-single module fiber laser; 7-laser power supply; 8-monitoring and controlling the host.
Detailed Description
The invention is described in detail below with reference to the figures and specific embodiments. It is noted that the aspects described below in connection with the figures and the specific embodiments are only exemplary and should not be construed as imposing any limitation on the scope of the present invention.
The embodiment of the invention discloses a fiber laser monitoring system which comprises a fiber laser and a sensor. The sensor is a sensing optical fiber or a sensing optical cable, and the sensor carries out continuous distributed real-time monitoring on temperature parameters in the optical fiber laser by utilizing a Raman scattering technology.
The principle of measuring the temperature by using the Raman (Raman) scattering effect is as follows: after laser output by the high-power narrow-pulse-width laser pulse semiconductor laser enters the sensing optical fiber, the laser interacts with molecules in the fiber core of the optical fiber to generate extremely weak back scattering light, and the scattering light has three wavelengths, namely Rayleigh (Rayleigh), anti-stokes (anti-Stokes) and stokes (Stokes) light; wherein the anti-stokes temperature is sensitive and is signal light sensed by the optical fiber; stokes temperature insensitive, reference light. The signal light backscattered from the sensing optical fiber passes through the light splitting module again to isolate Rayleigh scattered light, penetrates through the temperature-sensitive anti-stokes signal light and the temperature-insensitive stokes reference light, is received by the same detector (APD), and the temperature can be calculated according to the light intensity ratio of the two.
The invention adopts a full-scale continuous distributed optical fiber sensing mode, can accurately acquire the information of any point on the sensing optical fiber, and solves the problem of missing detection of the point sensor. In addition, the common communication optical fiber is adopted as a sensing unit, so that the cost of the sensor is greatly reduced.
Preferably, the sensor can adopt intrinsically safe passive optical fiber, has the advantages of insulativity, light weight, electromagnetic interference resistance and small volume, and is easy to integrate with an optical fiber laser system.
In a possible embodiment, the sensor further includes a positioning function, that is, based on an optical time-domain reflectometer (OTDR), the position of the optical fiber corresponding to the scattered signal is determined by measuring the echo time of the scattered signal through high-speed data acquisition. The technology can ensure that the positioning precision is within 0.1m, thereby accurately positioning the position and the area of the fault. Furthermore, the test light beam and the temperature monitoring sensing light beam of the optical time domain reflection technology are the same pulse laser, so that the temperature and the position information can be synchronously tested.
The length of the sensing fiber can extend over a length of several kilometers, so that the entire ten-kilowatt fiber laser can be detected. If the plurality of the myriawatt optical fiber lasers are close to each other, the operation condition of the plurality of the myriawatt optical fiber laser systems can be monitored. Therefore, the fiber laser can be a single-mode fiber laser of kilowatt level and above or a high-power multimode fiber laser consisting of a plurality of kilowatt level fiber laser modules. The output power of the single-module fiber laser is in kilowatt level, and the multimode fiber laser composed of a plurality of single modules is above kilowatt level and is high in dozens of kilowatt level. The output power of the common single-module optical fiber laser is 800W, 1000W, 1200W, 1500W, 2000W, 2500W, 3000W, 4000W and the like.
The existing single-module fiber laser is shown in fig. 1 and comprises an optical part, a structural part and an electric control part. The optical part is a core, and is a laser generating and outputting unit, and a semiconductor laser 1, a gain optical fiber 3, an optical fiber device 2 such as a beam combiner, an optical fiber grating, a cladding light filter and the like of an internal optical module, and an output head and the like of the optical module need to be monitored for temperature. The electronic control part such as the monitoring circuit board 4 is not only an output unit for alarming, but also a place which is easy to generate high temperature hidden trouble, and the monitoring part also needs to monitor.
In the embodiment of the present invention, a schematic diagram of routing of the sensing fiber 5 in the single-module fiber laser is shown in fig. 2, and the sensing fiber 5 is continuously laid on the semiconductor laser 1, the gain fiber 3, the fiber device 2, the monitoring circuit board 4, and other components, and only one sensing fiber 5 needs to be arranged in the whole module. For areas needing important monitoring, such as the semiconductor laser 1, the plurality of optical fiber devices 2 and the like, the sensing optical fiber 5 can be wound into a plurality of optical fiber rings to be laid above or around the area to be monitored, so that the monitoring accuracy is improved.
Further, the monitoring region of the sensing fiber 5 may further include a beam combining portion, a shutter portion and an output head portion of the fiber laser, and may even be connected to a laser processing device to monitor the operating temperature state of the laser processing device.
The sensing fiber 5 may be a single mode fiber for communication applications, or may be a multimode fiber, without limitation.
In another embodiment of the present invention, a schematic connection diagram of the sensing fiber 5 in the multi-module fiber laser is shown in fig. 3, and the sensing fiber 5 sequentially passes through each single-module fiber laser 6, passes through the laser power supply 7, and is connected to the monitoring and control host 8. The sensing optical fiber 5 exposed outside the module and the module needs to be covered with a plastic sheath or other sheaths for protection, the sensing optical fiber 5 exposed outside can also be made into an AC/PC joint, cold connection is realized through a flange plate, and the assembly and debugging of a high-power optical fiber laser system are facilitated.
The response time of the sensing optical fiber 5 is within 1s, the temperature resolution is within 0.1 ℃, and the temperature measurement precision is within 1 ℃. Within 1s, as long as the temperature of a certain point is found to be higher than or reach a preset temperature value, alarming sound is given out immediately or an electric control system of the optical fiber laser system is closed, and a light source is closed, so that the whole system is prevented from being damaged.
Corresponding to the distributed fiber laser monitoring system, the invention also discloses a fiber laser monitoring method, which adopts the sensing fiber as a sensor and utilizes the Raman scattering technology to carry out continuous distributed real-time monitoring on the temperature in the fiber laser.
In the prior art, it is generally difficult for those skilled in the art to think of using a sensing fiber as a sensor to monitor the internal temperature of a fiber laser. Although the patent CN103904532B uses a plastic optical fiber and a quartz optical fiber which are easily fused by heating as a sensing optical fiber to monitor a high-power optical fiber laser, the internal light passing of the sensing optical fiber is used as a transmission link of an optical switch, and the system is only powered off and protected after the sensing optical fiber is fused by heating. The scheme only takes the sensing optical fiber as simple optical switch protection, does not use a distributed optical fiber sensing technology, and does not have the functions of temperature measurement and positioning. The invention realizes distributed continuous monitoring by using the Raman scattering technology.
In addition, the monitoring method is not only suitable for the laser, but also suitable for the overall safety monitoring in laser processing equipment and high-energy laser weapon equipment, and only needs to extend the optical fiber for sensing to other positions on the equipment without excessive change.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.
The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
The above description is only a preferred example of the present application and should not be taken as limiting the present application, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present application should be included in the scope of the present application.
Claims (10)
1. A distributed fiber laser monitoring system is characterized in that: the optical fiber temperature sensor comprises an optical fiber laser and a sensor, wherein the sensor is a sensing optical fiber or a sensing optical cable, and the sensor carries out continuous distributed real-time monitoring on temperature parameters in the optical fiber laser by utilizing a Raman scattering technology.
2. The distributed fiber laser monitoring system of claim 1, wherein: the fiber laser is a kilowatt-level and above high-power single-mode fiber laser or a high-power multi-mode fiber laser consisting of a plurality of kilowatt-level single-mode fiber laser modules.
3. The distributed fiber laser monitoring system of claim 1, wherein: the response time of the sensor is within 1s, the temperature resolution is within 0.1 ℃, and the temperature measurement precision is within 1 ℃.
4. The distributed fiber laser monitoring system of claim 1, wherein: the monitoring area of the sensor comprises a semiconductor laser of the optical fiber laser, a gain optical fiber, an optical fiber device, a monitoring circuit board, a laser power supply and an output head.
5. The distributed fiber laser monitoring system of claim 1, wherein: the sensor employs intrinsically safe passive optical fibers.
6. The distributed fiber laser monitoring system of claim 1, wherein: the sensor comprises a positioning function, the positioning function adopts an optical time domain reflection technology, and the positioning precision is within 0.1 m.
7. The distributed fiber laser monitoring system of claim 6, wherein: the test light beam and the temperature monitoring sensing light beam of the optical time domain reflection technology are the same pulse laser.
8. The distributed fiber laser monitoring system of claim 2, wherein: when the fiber laser is a high-power multimode fiber laser, a sheath is laid on the sensor exposed out among the modules.
9. The distributed fiber laser monitoring system of claim 8, wherein: the external sensors between the modules are cold connected by means of flanges using AC/PC connections.
10. A distributed fiber laser monitoring method is characterized in that: and a sensing optical fiber or a sensing optical cable is used as a sensor, and the temperature in the fiber laser is continuously monitored in a distributed manner in real time by using a Raman scattering technology.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116720231A (en) * | 2023-06-13 | 2023-09-08 | 上海频准激光科技有限公司 | Data processing system of optical fiber laser layout |
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| JPH0555709A (en) * | 1991-08-29 | 1993-03-05 | Nec Corp | Cooling type semiconductor laser array module |
| CN201829809U (en) * | 2010-06-29 | 2011-05-11 | 深圳市雷迈科技有限公司 | Semiconductor laser module with various detection sensors and protectors |
| CN202197280U (en) * | 2011-08-30 | 2012-04-18 | 华南师范大学 | System integrating optical time domain reflectometer and distributed optical fiber Raman temperature sensor |
| CN104836099A (en) * | 2015-05-19 | 2015-08-12 | 大族激光科技产业集团股份有限公司 | Optical fiber laser system and monitoring device thereof |
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- 2020-09-29 CN CN202011048317.4A patent/CN112033574A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0555709A (en) * | 1991-08-29 | 1993-03-05 | Nec Corp | Cooling type semiconductor laser array module |
| CN201829809U (en) * | 2010-06-29 | 2011-05-11 | 深圳市雷迈科技有限公司 | Semiconductor laser module with various detection sensors and protectors |
| CN202197280U (en) * | 2011-08-30 | 2012-04-18 | 华南师范大学 | System integrating optical time domain reflectometer and distributed optical fiber Raman temperature sensor |
| CN104836099A (en) * | 2015-05-19 | 2015-08-12 | 大族激光科技产业集团股份有限公司 | Optical fiber laser system and monitoring device thereof |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116720231A (en) * | 2023-06-13 | 2023-09-08 | 上海频准激光科技有限公司 | Data processing system of optical fiber laser layout |
| CN116720231B (en) * | 2023-06-13 | 2024-01-26 | 上海频准激光科技有限公司 | Data processing system of optical fiber laser layout |
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Application publication date: 20201204 |