CN207472421U - A kind of high-capacity optical fiber laser light echo monitors optical module - Google Patents

Abstract

The embodiment of the utility model provides an optical module for monitoring the return light of a high-power fiber laser, and the optical module includes an energy transmission optical fiber, a package heat dissipation base, a filter adhesive layer and a photodetector. The heat dissipation base of the package includes a strip-shaped heat sink and a groove arranged along the length direction on the heat sink; the stripped section of the coating layer of the energy-transmitting optical fiber is placed in the groove; The light-curable adhesive is formed after curing, which tightly wraps the stripped section of the coating layer and fits closely with the groove; the photodetector is arranged in the photometric area at the end of the filter adhesive layer along the light transmission direction. The optical module of the utility model evaluates the return light introduced by the high-power fiber laser output system by monitoring the return light in the filtered cladding light. Compared with traditional devices, it can withstand higher power, lower manufacturing cost, and simple manufacturing process. , has lower requirements on the process platform, and can further improve the beam quality of the output laser.

Description

A high-power fiber laser light return monitoring optical module

technical field

The utility model belongs to the technical field of fiber laser applications, in particular to an optical module suitable for high-power fiber laser return light monitoring.

Background technique

With the maturity of fiber laser production technology, high-power fiber lasers have been widely used in industrial processing fields, such as high-power fiber lasers can be used for laser cutting of various metals. Laser cutting is a processing technology that melts or vaporizes materials instantly through a high-energy-density laser beam, and at the same time uses an auxiliary airflow to blow off the material to form a slit. It has the characteristics of high processing efficiency and good product quality. Fiber laser is used as the source of laser beam , it is easier to obtain high-quality and high-power-density laser beams, and the processing cost is lower, and it is more and more widely used in the field of laser cutting.

In the field of metal material processing today, the processing of highly reflective materials, such as copper, aluminum, gold and other metals, occupies a very high share in the total processing. However, due to the high reflectivity and physical characteristics of such materials, the introduction of retro The light will cause serious damage to the fiber laser, the core component of the laser cutting machine, and greatly reduce the service life of the fiber laser. It can be seen from the above that when using lasers for industrial processing, it is particularly important to reasonably and effectively monitor the return light caused by the fiber laser output system and subsequent parts. For small and medium power fiber lasers, the return light in the optical path can be effectively monitored and controlled by couplers, isolators and other devices, but the high power fiber lasers used in the field of laser industrial processing are usually 500 watts or even kilowatts. Under the working conditions of high-power lasers, the light return monitoring technology of the above-mentioned small and medium-power lasers is no longer applicable. Therefore, developing a backlight monitoring technology suitable for high-power fiber lasers has become a technical problem to be solved urgently.

Utility model content

What the utility model aims to solve is the technical problem that the existing optical fiber laser return light monitoring technology is not suitable for high-power optical fiber lasers.

In order to solve the above technical problems, the embodiment of the utility model provides a high-power fiber laser light return monitoring optical module, including energy transmission optical fiber, package heat dissipation base, filter adhesive layer and optical detector, wherein:

The package heat dissipation base includes a strip-shaped heat sink and a groove arranged on the heat sink along the length direction; the stripped section of the coating layer formed after the energy-transmitting optical fiber is stripped is placed in the groove Middle; the filter adhesive layer is a bonding material with a higher refractive index than the coating layer of the energy-transmitting optical fiber, which tightly wraps the stripped section of the coating layer and fits closely with the groove, and the coating layer The layer peeling section is fixed in the groove; the end part of the filter adhesive layer located along the light transmission direction is the photometry area, and the rest is the light guide area, and the photodetector is arranged in the photometry area .

Preferably, the groove is straight or curved, and its cross-sectional shape can be V-shaped, U-shaped or rectangular, or other cross-sectional shapes.

Preferably, the refractive index of the filter adhesive layer varies along the light transmission direction in the energy-transmitting optical fiber, and the refractive index of the light-measuring area is greater than that of the light-guiding area.

Further preferably, the refractive index of the filter adhesive layer can be set to increase continuously along the light transmission direction in the energy-transmitting optical fiber, or it can also be set to increase step by step, or to increase along the direction of light transmission in the energy-transmitting optical fiber The direction of light transmission remains unchanged.

Preferably, the refractive index of the photometric region is greater than the refractive index of the inner cladding.

Preferably, the filter adhesive layer is formed by curing an ultraviolet light curing adhesive with an ultraviolet lamp.

Preferably, the photosensitive surface of the photodetector is buried in the photometric area of the filter adhesive layer or is closely attached to the photometric area; the photodetector can be selected to correspond to the energy transmission optical fiber Photodiode in the medium signal light band.

The beneficial effects of the utility model are as follows: the above-mentioned technical scheme of the embodiment of the utility model realizes the purpose of monitoring the laser output system to introduce the returning light by filtering the returning light in the cladding and monitoring, and has the following beneficial effects:

1. By monitoring the returned light in the filtered cladding light, the returned light introduced by the subsequent system is evaluated. Compared with the traditional tapered and space-coupled returned light monitoring devices, there is basically no paired core waveguide The destruction or recoupling of the characteristics, the insertion loss of the signal light is low, and the power can be high, especially suitable for high-power fiber lasers;

2. The method of filtering cladding light is adopted in the process of returning light monitoring, and the introduction of the optical module of the utility model in the fiber laser system can further improve the beam quality of the output laser;

3. Compared with traditional tapered and space-coupled return light monitoring devices, the optical module of this utility model has low manufacturing cost, simple manufacturing process, and lower requirements on the process platform.

Description of drawings

Fig. 1 is the structural schematic diagram of existing double-clad energy transmission optical fiber;

Fig. 2 is a cross-sectional schematic diagram of a high-power fiber laser light return monitoring optical module provided by an embodiment of the utility model;

Fig. 3 is a schematic structural diagram of a high-power fiber laser light return monitoring optical module provided by an embodiment of the present invention.

[Description of main component symbols]

1-energy transmission fiber; 10-coating layer peeling section; 11-core; 12-inner cladding; 13-outer cladding; 14-coating; 2-heat sink; 21-groove; 3-filter glue layer; 31-light guide area; 32-light metering area; 4-photodetector; D-light transmission direction.

Detailed ways

In order to make the technical problems, technical solutions and advantages to be solved by the utility model clearer, the following will describe in detail with reference to the drawings and specific embodiments.

In order to solve the technical problem that the optical fiber laser return light monitoring technology in the prior art is not suitable for high-power laser working conditions, the embodiment of the utility model provides a high-power fiber laser light return monitoring optical module. The components of the optical module include Energy transmission optical fiber 1 , encapsulation heat dissipation base, filter adhesive layer 3 and photodetector 4 .

The energy transmission fiber 1 should match the output system fiber of the fiber laser, and can be a whole fiber or a fused fiber. Because double-clad fibers are often used in current high-power fiber lasers, for the convenience of description, this embodiment takes double-clad fiber lasers as an example, and the energy transmission fiber 1 is a whole commercial double-clad fiber that matches the output system fiber. The basic structure of a commonly used double-clad energy-transmitting optical fiber 1 is shown in Figure 1. Its radial direction is a concentric layered structure, and the layers are respectively core 11, inner cladding 12, outer cladding 13 and coating from inside to outside. Layer 14, the corresponding refractive indices are n11, n12, n13, n14 respectively, wherein n11>n12>n13>n14.

As shown in Figure 2 and Figure 3, the specific implementation is as follows:

The heat dissipation base of the optical module package in this embodiment includes a columnar heat sink 2 and a groove 21 arranged along the length direction on the heat sink 2, which is used to accommodate the energy transmission optical fiber 1 and the filter adhesive layer 3 and to dissipate heat for the entire optical module. The peeling section 10 of the coating layer formed after the energy-transmitting optical fiber 1 is stripped is placed in the groove 21; The peeling section 10 of the coating layer is closely attached to the groove 21, and the peeling section 10 of the coating layer is fixed in the groove 21; Part of it is the light guiding area 31 , and the photodetector 4 is arranged in the light measuring area 32 .

As a specific embodiment, the groove 21 can be linear or curved, and its cross-sectional shape is V-shaped, U-shaped or rectangular. Slot shape. As shown in FIG. 2 , as an implementation, the energy-transmitting optical fiber 1 is fixed at the center of the groove 21 in the package heat dissipation base through the optical filter adhesive layer 3 , and the groove 21 adopts a rectangular cross section.

As an embodiment, the coating layer stripping section 10 can be formed by stripping a section of coating layer in the middle of the energy-transmitting optical fiber 1 with a blade. The length of the coating layer stripping section 10 should match the groove 21, and the length is usually about 7 cm. That's it. During the stripping process of the coating layer, care should be taken to avoid damage to the inner cladding as much as possible, and the stripping section 10 of the coating layer can be cleaned with alcohol after stripping.

As a preferred embodiment, the adhesive material of the filter adhesive layer 3 is a UV-curable adhesive specially used for high-refractive-index optical fibers. The refractive index of the UV-curable adhesive should be greater than that of the stripped coating layer. Post curing molding. In order to ensure the quality of the filter adhesive layer 3, it is necessary to ensure that there are no air bubbles in the glue during the filling process of the ultraviolet light curing adhesive, and to pay attention to the appropriate irradiation power and height when the ultraviolet lamp is irradiated and cured.

As shown in FIG. 3 , the optical fiber UV-curable adhesive is filled in the entire groove 21 to form a coating layer stripping section 10 , and the filter adhesive layer 3 is divided into a light guiding area 31 and a photometric area 32 along the light transmission direction D. As a preferred embodiment, the refractive index of the UV-curable adhesive gradually increases along the light transmission direction in the groove 21, the refractive index of the photometric area is greater than that of the inner cladding, and the refractive index of the photometric area 32 is greater than that of the light guide area 31. The refractive index of the optical filter glue layer 3 can increase continuously along the light transmission direction D or step by step, or remain unchanged. In the coating stripping section 10 formed after stripping the coating of the energy-transmitting optical fiber 1, the fiber cladding is in a bare state, and after the coating stripping section 10 is wrapped with a high refractive index filter adhesive layer 3, the cladding When the remaining pumping light and return light in the filter are transmitted to the optical filter adhesive layer 3, they enter the optical filter adhesive layer 3 because the total reflection condition cannot be satisfied; the refractive index of the optical filter adhesive layer 3 is set to increase along the light transmission direction D It is beneficial to separate the pumping light and return light at different angles.

The photodetector 4 is installed at the corresponding position of the heat dissipation base of the package, and can be fixed with thermally conductive glue. The selection of the optical detector 4 should consider the wavelength of the signal light passed by the energy-transmitting optical fiber 1, and a photodetector element with a better response at the corresponding wavelength should be selected, such as a photoelectric diode corresponding to the signal light band in the energy-transmitting optical fiber 1; The setting method of the photosensitive surface of the detector 4 should consider the shape and size of the groove 21, and the photosensitive surface should be embedded in the photometric area 32 of the filter adhesive layer 3 or be closely attached to the photometric area 32. In an embodiment, it can be adjusted so that the relative positions of the coating layer stripping section 10 and the photodetector 4 are as shown in FIG. 3 .

In particular, it should be noted that when the optical module is connected in the system, strict attention should be paid to the direction of light transmission. After accessing the system, the transmission direction of the signal light on the module must be strictly consistent with the marked optical transmission direction D, as shown in Figure 3.

The utility model achieves the purpose of monitoring the return light introduced into the laser output system by filtering and monitoring the return light in the cladding layer. Compared with traditional tapered and space-coupled devices, there is basically no damage to the transmission characteristics of the core waveguide, and the insertion loss generated by the signal light is low, and the withstand power is high. It is more prominent in high-power fiber lasers, especially fiber laser systems with kilowatts or even higher power. The introduction of the optical module can also filter out the high-order mode laser of the residual pump light in the cladding of the fiber, thereby improving the quality of the output laser beam. The utility model has low production cost, simple production process and low requirements on the process platform.

For the above-mentioned embodiments of the present utility model, common knowledge such as specific structures and characteristics known in the scheme are not described too much; each embodiment is described in a progressive manner, and the technical characteristics involved in each embodiment are different from each other. They can be combined with each other on the premise that no conflict is formed, and the same and similar parts of the various embodiments can be referred to each other.

The above is a preferred implementation structure of the utility model device, which is only a preferred embodiment of the utility model, and does not limit the patent scope of the utility model. Under the premise of not departing from the principle of the utility model, any Equivalent structures made by using the description of the utility model and the accompanying drawings are all included in the protection scope of the utility model patent.

Claims (8)

1. A high-power fiber laser light return monitoring optical module, characterized in that it includes an energy-transmitting optical fiber (1), a package heat dissipation base, a filter layer (3) and a photodetector (4), wherein: The package heat dissipation base includes a strip-shaped heat sink (2) and a groove (21) provided along the length direction on the heat sink (2); the energy transmission optical fiber (1) is formed after stripping the coating layer The peeling section (10) of the coating layer is placed in the groove (21); the filter adhesive layer (3) is a bonding material with a higher refractive index than the coating layer of the energy transmission optical fiber (1), which is tightly Wrapping the coating peeling section (10) and closely fitting the groove (21), fixing the coating peeling section (10) in the groove (21); the filter The end part of the photoresist layer (3) located along the light transmission direction is the photometry area (32), and the rest is the light guide area (31), and the photodetector (4) is arranged in the photometry area (32) middle. 2. The optical module according to claim 1, characterized in that, the groove (21) is straight or curved, and its cross-sectional shape is V-shaped, U-shaped or rectangular. 3. The optical module according to Claim 1, characterized in that, the refractive index of the photometry area (32) of the filter adhesive layer (3) is greater than or equal to the refractive index of the light guide area (31). 4. The optical module according to claim 3, characterized in that, the refractive index of the filter adhesive layer (3) increases continuously or step by step along the light transmission direction in the energy-transmitting optical fiber (1) . 5. The optical module according to claim 3, characterized in that, the refractive index of the filter adhesive layer (3) remains constant along the light transmission direction in the energy transmission optical fiber (1). 6 . The optical module according to claim 1 , wherein the filter adhesive layer ( 3 ) is formed by curing an ultraviolet light curing adhesive with an ultraviolet lamp. 7 . 7. The optical module according to any one of claims 1 to 6, characterized in that, the photosensitive surface of the photodetector (4) is buried in the photometric area ( 32) or in close contact with the photometric area (32). 8 . The optical module according to claim 7 , characterized in that, the optical detector ( 4 ) is a photodiode corresponding to the band of signal light in the energy transmission optical fiber ( 1 ).