CN205785514U - All-fiber power measurement system for high-power fiber laser - Google Patents

Abstract

The utility model discloses an all-fiber power measurement system used for high-power fiber lasers, aiming at solving the problems that the traditional measurement system is complex in structure and easily deteriorates the quality of output beams. The utility model comprises an output optical fiber connected with the optical fiber laser to be tested, a light energy sampling unit, a photoelectric detector, a data acquisition unit, a data processing unit and a display unit. The optical energy sampling unit includes a coupling optical fiber; the output optical fiber has a first decoating area, and the coupling optical fiber has a second decoating area; the first decoating area and the second decoating area are fixed with optical glue to form an optical energy coupling area; part of the light energy in the output fiber is transferred to the coupling fiber through the light energy coupling area to realize light energy sampling. The photodetector is used to detect the output signal of the coupled optical fiber; the data acquisition unit is used to collect the output signal of the photodetector; the data processing unit is used to obtain the output power of the fiber laser to be tested; the display unit is used to display the output power.

Description

An all-fiber power measurement system for high-power fiber lasers

technical field

The utility model belongs to the field of photoelectric detection and relates to an all-fiber power measurement system for high-power fiber lasers.

Background technique

At present, as a new type of solid-state laser, high-power fiber laser is widely used in industrial processing, 3D printing, laser medical treatment, military defense and other fields because of its high conversion efficiency, good beam quality, compact structure and high output power. In practical applications, due to the temperature drift of the pump source, the heat of the gain fiber, and the working environment, the output power of high-power fiber lasers is usually unstable. Therefore, whether it is in general industrial processing, 3D printing or laser medical treatment, online monitoring of the output power of fiber lasers is required.

The general online measurement method of laser output power is to use a spectroscopic device for spectroscopic measurement, that is, to sample from the output power, and then measure the sampled part. Traditional high-power fiber laser power measurement sampling methods are generally divided into two types: using spatially discrete devices (such as beam splitters) and fiber insertion devices (such as beam splitters). The high beam splitting ratio beam mirror used in the sampling method using spatially discrete devices requires spatial adjustment, which reduces the mechanical stability of the fiber laser, and is difficult to manufacture and high in cost. In addition, the thermal lens effect of the beam splitter will degrade the beam quality of the output laser. Although the sampling method using the fiber beam splitter has high mechanical stability, the insertion of the fiber beam splitter will cause perturbation to the fiber waveguide structure, causing mode coupling, which will lead to the deterioration of the beam quality; The destruction of the integrity will cause the fiber to heat up and affect the safety of the entire system; in addition, the fiber splitter with a lower splitting ratio will reduce the output power of the system, while the fiber splitter with a high splitting ratio is difficult to manufacture. Therefore, in actual engineering applications, the traditional online monitoring of laser output power has complex structure, high cost, and low safety factor, and is not suitable for real-time online monitoring of high-power fiber laser output power. Therefore, a more effective online monitoring method is designed. Measurement systems are important.

Utility model content

In order to solve the problem of complex structure of traditional on-line monitoring laser output power and easy to deteriorate the quality of the output laser beam in the above-mentioned background technology, the utility model provides an all-fiber power measurement system for high-power fiber lasers.

The technical solution of the utility model is:

An all-fiber power measurement system for a high-power fiber laser, comprising an output fiber, an optical energy sampling unit, a photodetector, a data acquisition unit, a data processing unit, and a display unit; the output fiber is connected to the fiber laser to be measured; The data acquisition unit is used to collect the output signal of the photodetector; the data processing unit is used to obtain the output power value of the fiber laser to be tested; the display unit is used to display the output power value of the fiber laser to be tested.

Its special features are:

The optical energy sampling unit includes a coupling optical fiber;

The output optical fiber has a first uncoated area, and the coupling optical fiber has a second uncoated area; the first uncoated area and the second uncoated area are fixed with optical glue to form an optical energy coupling area; Part of the light energy in the output fiber is transferred to the coupling fiber through the light energy coupling region for transmission, so as to realize light energy sampling;

The photodetector is located at the output end of the coupling optical fiber and is used for detecting the optical signal output by the coupling optical fiber.

Based on above-mentioned basic technical scheme, the utility model can make following optimization:

In order to enhance the coupling sampling effect of the coupling fiber, the second decoating area of the coupling fiber is a tapered fiber, and the tapered uniform part and the second decoating area are fixed with optical glue.

The above-mentioned output fiber and coupling fiber are packaged and fixed in the light energy coupling area with a package shell to enhance the stability of the power measurement system.

The utility model has the advantages of:

1. The optical energy sampling unit of the utility model adopts an all-fiber structure, and uses optical fiber evanescent wave coupling to transfer a very small part of laser energy from the output optical fiber to the coupling optical fiber for transmission. This method does not need to insert a beam splitter, or The optical device is inserted on the road without destroying the all-fiber structure of the fiber laser, avoiding unnecessary disturbance to the output laser, and realizing the interference-free online measurement of high-power fiber laser.

2. The utility model does not need to withstand strong laser irradiation, and has no laser damage threshold problem, and can be used for high-power, high-energy fiber laser sampling and on-line monitoring.

3. The utility model has the advantages of simple structure, safety and reliability, low cost and easy implementation.

Description of drawings

Fig. 1 is the schematic diagram of the online power measuring system of the present utility model;

Fig. 2 is a schematic diagram of light energy sampling in the present invention.

detailed description

As shown in Figure 1, the all-fiber power measurement system for high-power fiber lasers provided by the utility model includes an output fiber, an optical energy sampling unit, a photoelectric detector, a data acquisition unit, a data processing unit, and a display unit.

The output fiber 2 is connected to the high-power fiber laser 1 ; a section of the output fiber 2 is decoated to form a first decoated area 11 .

The optical energy sampling unit 3 includes a coupling fiber 6 ; a section of a certain position of the coupling fiber 6 is decoated to form a second decoating region 12 .

The first uncoated area 11 and the second uncoated area 12 are fixed by optical glue to form an optical energy coupling area 13 . In order to further enhance the stability of the power measurement system, the output optical fiber 2 and the coupling optical fiber 6 are fixed with optical glue in the optical energy coupling area 13 and then packaged and fixed with a packaging shell.

Due to defects in the fiber manufacturing process, fiber fusion splicing and interference of fiber device insertion, when the laser is transmitted in the output fiber 2, it is mainly transmitted in the core mode 9, and part of the laser will be coupled into the cladding to form a cladding mode 10 transmission. Therefore, when the first decoating region 11 and the second decoating region 12 are close or close together, part of the light energy transmitted in the cladding mode 10 in the output laser will be transferred to the coupling fiber 6 for transmission, thereby realizing light energy sampling .

The length of the light energy coupling region 13 is determined by the parameters of the two optical fibers (output fiber and coupling fiber) in the light energy coupling region 13, the close distance and the expected coupling efficiency. In this embodiment, the length of the light energy coupling region 13 is 1 cm.

The photodetector 5 is located at the output end of the coupling optical fiber 6, and is used to detect the optical signal output by the coupling optical fiber 6, and convert the detected optical signal into an electrical signal for output;

The data acquisition unit 7 is connected with the photodetector 5 and used for collecting the output signal of the photodetector 5 . The data acquisition unit 7 of the present embodiment is made up of pre-amplification circuit and A/D conversion circuit, adopts pre-amplification circuit to amplify the output signal of photodetector 5, utilizes A/D conversion circuit to the signal after being amplified then Perform data collection.

The data processing unit 8 is used to obtain the output power value of the fiber laser to be tested.

The display unit 14 is used to display the output power value of the fiber laser to be tested.

Before using the power measurement system provided by the utility model to monitor the power of the fiber laser 1 online, the utility model needs to be calibrated in advance, and the specific calibration method is:

1. A power meter is installed at the output end of the output fiber 2 to measure the output power of the high-power fiber laser 1 .

2. Calibrate the linear relationship between the output signal (voltage, etc.) of the photodetector and the output power of the fiber laser (that is, calibrate the power measurement system):

2.1 The data acquisition unit collects the output power signal of the high-power fiber laser 1 and the output signal of the photodetector;

2.2 The data processing unit processes the signal obtained by the data acquisition unit in the above step 2.1 to obtain the corresponding relationship between the output signal (voltage, etc.) of the photodetector 5 and the output power of the high-power fiber laser 1 .

After the power measurement system of the present utility model is calibrated according to the above method, the data processing unit obtains the output of the high-power fiber laser 1 according to the corresponding relationship between the output signal (voltage, etc.) of the photodetector 5 and the output power of the high-power fiber laser 1 Power value, and display the measurement results at the same time, realizing real-time online measurement of the output power of high-power fiber lasers.

Claims (3)

1. for an all-fiber power measuring system for high-capacity optical fiber laser, including output optical fibre, light energy sampling list Unit, photodetector, data acquisition unit, data processing unit and display unit；Described output optical fibre and testing fiber laser Device is connected；Described data acquisition unit is for gathering the output signal of photodetector；Described data processing unit is used for obtaining The output power value of testing fiber laser instrument；Described display unit is for showing the output power value of testing fiber laser instrument；

It is characterized in that:

Described light energy sampling unit includes coupling optical fiber；

Described output optical fibre has first and goes to coating area, described coupling optical fiber to have second to go to coating area；Described first goes coating District and second goes to coating area to use optical cement to fix, and forms light energy coupled zone；Part light energy in described output optical fibre is led to Cross described light energy coupled zone to transfer to described coupling optical fiber transmits, it is achieved light energy samples；

Described photodetector is positioned at the outfan of coupling optical fiber, for detecting the optical signal that coupling optical fiber is exported.

A kind of all-fiber power measuring system for high-capacity optical fiber laser the most according to claim 1, its feature It is: the second of described coupling optical fiber goes to coating area to be tapered fiber, and the uniform parts of its taper and second goes to coating area to use Optical cement is fixed.

A kind of all-fiber power measuring system for high-capacity optical fiber laser the most according to claim 1 and 2, it is special Levy and be: described output optical fibre and coupling optical fiber use in light energy coupled zone package casing encapsulation fixing.