Reflection-light-resistant laser output head

Abstract

The utility model discloses a laser output head capable of resisting return light, which sequentially comprises an optical fiber, a reflecting mirror group, a cladding light mode stripper and a quartz head along the propagation direction of working laser, and further comprises an optical fiber fixing ring and an inner sleeve, the optical fiber fixing ring fixes the optical fiber at the first end of the inner sleeve, the quartz head is embedded into the second end of the inner sleeve, and the optical fiber penetrates through the inner sleeve to be connected with the quartz head; and the reflecting mirror group is sleeved on the optical fiber. According to the laser output head provided by the utility model, the return light conducted to the tail fiber stripping port is less, the heat which is reflected by the reflector group and is further absorbed by the cavity can be rapidly taken away by water cooling, and compared with the prior art, the anti-return power threshold can be improved by about 35%.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of laser output head, concretely relates to a laser output head of anti return light. BACKGROUND

[0002] High-power fiber laser has important application in the field of material processing, and can be used for cutting, welding, punching and the like of metal materials and the like. Fiber laser has small spot diameter and high energy density, and for metal materials, can realize high-efficiency and high-quality welding and cutting. Laser output head plays an important role as a core component of high-power fiber laser. In the laser processing process, due to the fact that the workpiece cannot absorb all the laser, especially when processing high-reflectivity materials, part of the laser will return to the laser output head and enter the fiber cladding, causing damage to the laser system.

[0003] In the prior art, to solve the above problems, a cladding light mode stripper is additionally arranged on the fiber to reduce the return light propagating along the cladding, and water cooling is performed outside the laser output head cavity. Meanwhile, the tail fiber stripping port is fixed on the heat-conducting fixing member, and the heat-conducting fixing member is in contact with the laser output head cavity and is fixed indirectly, thereby achieving indirect heat dissipation. This method mainly removes the heat in the cavity, and to some extent, can improve the anti-return light capability of the laser output head, but the heat dissipation capability of the fiber stripping port is limited, and the fiber coating at the stripping port can be burnt due to the excessively high return light power, and the application reliability of the laser still faces challenges. UTILITY MODEL CONTENTS

[0004] The utility model aims at providing a laser output head of anti-return light, which can improve the return light power damage threshold of the laser output head.

[0005] In order to achieve the above-mentioned purpose, the utility model provides a laser output head of anti-return light, which comprises, in sequence along the propagation direction of working laser, a fiber, a mirror group, a cladding light mode stripper and a quartz head, and further comprises a fiber fixing ring and an inner cylinder sleeve.

[0006] Preferably, the laser output head further comprises a shell, which is arranged outside the inner cylinder sleeve, and a water cooling connector is arranged on the shell and connected with external circulating cooling liquid.

[0007] Preferably, the mirror group is arranged close to the first end of the inner cylinder sleeve.

[0008] Preferably, the mirror set comprises at least a first mirror and a second mirror, and the first mirror and the second mirror are coated with a high reflection film towards the face of the quartz head.

[0009] Preferably, the high reflection film has a reflectivity of no less than 99.8% to the back-returning light.

[0010] Preferably, a glass tube is arranged between the first mirror and the second mirror.

[0011] Preferably, the length of the glass tube is 3-5mm.

[0012] Preferably, the outer diameter of the first mirror and the second mirror is 4-6mm, and the inner diameter is 0.4-0.8mm.

[0013] Preferably, the stripping efficiency of the cladding light stripper to the back-returning light is no less than 95%.

[0014] The laser output head provided by the utility model has the advantages that: the back-returning light conducted to the tail fiber stripping opening is less, the heat further absorbed by the cavity after being reflected by the mirror set can be quickly taken away by water cooling, and the anti-back-returning power threshold can be increased by about 35% compared with the prior art. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is the structure diagram of the laser output head against back-returning light provided by the utility model.

[0016] In the figure: 1-fiber; 2-fiber fixing ring; 3-inner sleeve; 4-outer shell; 41-water cooling connector; 5-cladding light stripper; 6-quartz head; 7-mirror set; 71-first mirror; 72-second mirror; 8-glass tube. DETAILED DESCRIPTION

[0017] The technical scheme of the utility model will be further illustrated by specific embodiments in combination with the drawings.

[0018] The utility model provides a kind of laser output head against back-returning light, mirror set with diaphragm aperture is increased between laser output head cavity and tail fiber stripping opening and the rest position is coated with high reflection film, and the back-returning light returned to laser output head is scattered after being absorbed by cavity after being reflected by cladding light stripper, and the part is propagated to the coated film area of mirror set, and is returned to cavity after being reflected by coated film area, and is further absorbed by cavity.This way, the light conducted to tail fiber stripping opening is reduced, so as to reduce the heat of tail fiber stripping opening, reduce the temperature of tail fiber stripping opening;While the heat further absorbed by cavity after being reflected by mirror set can be quickly taken away by water cooling, and the anti-back-returning capacity of laser output head is obviously improved.

[0019] As Figure 1As shown, along the propagation direction of the working laser, the laser output head comprises, in sequence, the optical fiber 1, the mirror group 7, the cladding light stripper 5 and the quartz head 6. The laser output head further comprises the optical fiber fixing ring 2 and the inner sleeve 3. The optical fiber fixing ring 2 fixes the optical fiber 1 at the first end of the inner sleeve 3, the quartz head 6 is embedded in the second end of the inner sleeve 3, and the optical fiber 1 passes through the inner sleeve 3 and is connected with the quartz head 6. The laser output head can further comprise the shell 4 arranged outside the inner sleeve 3, and the shell 4 is further provided with a water cooling connector 41 connected with an external circulating coolant, which is used to cool the laser output head so that the laser output head works in a suitable temperature range. In other embodiments, air cooling or other cooling methods can be used to cool the inner sleeve 3.

[0020] The mirror group 7 is arranged close to the first end of the inner sleeve and is sleeved on the optical fiber 1. In this embodiment, the mirror group 7 comprises the first mirror 71 and the second mirror 72, and the surfaces of the first mirror 71 and the second mirror 72 facing the quartz head 6 are coated with a high reflection film with a reflectivity of not less than 99.8% for the return light. In other embodiments, the mirror group 7 can comprise more than two mirrors.

[0021] The cladding light stripper 5 is used to effectively strip the return cladding light propagating in the opposite direction, and can be made by a laser etching process, and has a stripping efficiency of not less than 95% for the return light. When the return light enters the cladding of the optical fiber 1, it is stripped by the cladding light stripper 5 and scattered to the inner wall of the inner sleeve 3, and most of the light is absorbed by the inner wall of the inner sleeve 3 and converted into heat, which is carried away by the circulating coolant. A small part of the return light that is not absorbed by the inner sleeve 3 propagates to the second mirror 72, is reflected by the second mirror 72 to the inner wall of the inner sleeve 3 and is further absorbed. Another small part of the return light that is not reflected by the second mirror 72 continues to propagate to the first mirror 71, is reflected by the first mirror 71 to the inner wall of the inner sleeve 3 and is further absorbed.

[0022] Optionally, a glass tube 8 connecting the first mirror 71 and the second mirror 72 is arranged between the first mirror 71 and the second mirror 72, and the length of the glass tube 8 is 3-5 mm. Optionally, the outer diameter of the first mirror 71 and the second mirror is 4-6 mm, and the inner diameter is 0.4-0.8 mm.

[0023] The laser output head provided by the utility model has less return light conducted to the stripping opening of the pigtail, and the heat generated by the return light reflected by the mirror group and further absorbed by the cavity can be quickly carried away by water cooling, so that the anti-return power threshold can be increased by about 35% compared with the prior art.

[0024] The technical principles of the present application are described above in combination with specific embodiments. These descriptions are only for explaining the principles of the present application, and cannot be interpreted as limiting the protection scope of the present application in any way. Based on the explanations herein, other specific embodiments of the present application can be conceived by those skilled in the art without creative efforts, and these embodiments will all fall within the protection scope of the present application.

Claims

1. A laser output head against return light, characterized by comprising: The laser output head comprises, in sequence along the propagation direction of the working laser, a fiber, a mirror group, a cladding light stripper and a quartz head, and further comprises a fiber fixing ring and an inner sleeve; the fiber fixing ring fixes the fiber at the first end of the inner sleeve, the quartz head is embedded in the second end of the inner sleeve, the fiber passes through the inner sleeve and is connected with the quartz head; the mirror group is arranged on the fiber.

2. The anti-backlash laser output head of claim 1, wherein, The laser output head further comprises an outer shell, which is arranged outside the inner sleeve, and a water cooling connector is arranged on the outer shell and connected with an external circulating coolant.

3. The anti-backlash laser output head of claim 1, wherein, The mirror group is arranged close to the first end of the inner sleeve.

4. The anti-backlash laser output head of claim 3, wherein, The mirror group comprises at least a first mirror and a second mirror, and the surfaces of the first mirror and the second mirror facing the quartz head are coated with a high reflection film.

5. The anti-backlash laser output head of claim 4, wherein, The reflectivity of the high reflection film to the back-returning light is not less than 99.8%.

6. The anti-backlash laser output head of claim 4, wherein, A glass tube connecting the first mirror and the second mirror is arranged between the first mirror and the second mirror.

7. The anti-backlash laser output head of claim 6, wherein, The length of the glass tube is 3-5 mm.

8. The anti-backlash laser output head of claim 4, wherein, The outer diameter of the first mirror and the second mirror is 4-6 mm, and the inner diameter is 0.4-0.8 mm.

9. The anti-backlash laser output head of claim 1 wherein, The stripping efficiency of the cladding light stripper to the back-returning light is not less than 95%.

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