CN116191176B

CN116191176B - Fiber laser output head comprising pump stripping and mode filtering functions and manufacturing method thereof

Info

Publication number: CN116191176B
Application number: CN202211556643.5A
Authority: CN
Inventors: 王晨晟; 姚佳成; 崔索超; 尚俊杰; 郑建奎; 戚亦乐; 陈炯
Original assignee: 717Th Research Institute of CSSC
Current assignee: 717Th Research Institute of CSSC
Priority date: 2022-12-06
Filing date: 2022-12-06
Publication date: 2025-11-11
Anticipated expiration: 2042-12-06
Also published as: CN116191176A

Abstract

This invention discloses a fiber laser output head including pump stripping and mode filtering functions, comprising a metal base, a metal top cover, a pigtail, an output cap, and a thermally conductive substrate. The metal base and metal top cover form a space for placing the pigtail and the output cap. The pigtail passes through a pigtail hole and is fused to the output cap. A UV optical adhesive is applied to the coating layer of the pigtail near the pigtail hole. On the pigtail, a bare fiber etched area and a bare fiber adhesive application area are sequentially arranged towards the output cap. A thermally conductive substrate is provided below the bare fiber adhesive application area. High-refractive-index UV optical adhesive is filled between the bare fiber adhesive application area and the thermally conductive substrate, and the UV optical adhesive is used to fix the thin cylindrical side of the output cap. This invention also provides a method for manufacturing the aforementioned fiber laser output head including pump stripping and mode filtering functions. This invention can shorten the pigtail length between the CPS and the output head, reduce the laser volume, and make the optical axes of the pigtail and the output head lie in the same horizontal plane.

Description

Fiber laser output head comprising pump stripping and mode filtering functions and manufacturing method thereof

Technical Field

The invention belongs to the technical field of optical fiber devices, and particularly relates to an optical fiber laser output head with pump stripping and mode filtering functions and a manufacturing method thereof.

Background

At present, since the suspended device tail fiber between a pump stripper (CPS) and an output head or a collimator, which are positioned behind a gain fiber, of most fiber lasers is long, a large volume needs to be occupied in the lasers, and the tail fiber output by the pump stripper and the optical axis mounting height of the output head are not in the same horizontal plane, various nonlinear effects including Amplified Spontaneous Emission (ASE), self-phase modulation (SPM), stimulated Raman Scattering (SRS) and the like are easily caused in high-power application and ultrafast laser application, and the suspended tail fiber is easily subjected to external disturbance such as stress variation and the like, so that output characteristic indexes such as power, pulse width, spectrum width, beam quality and the like of the fiber lasers are influenced.

Disclosure of Invention

The invention aims to provide an optical fiber laser output head with pump stripping and mode filtering functions and a manufacturing method thereof, which can shorten the length of a suspended device tail fiber between a pump stripper (CPS) and an output head or a collimator, reduce the volume of a laser, integrate the device tail fiber with an output end cap, and enable the mounting height of an optical axis of the output tail fiber and the output head to be positioned in the same horizontal plane.

The technical scheme adopted by the invention is as follows:

the fiber laser output head comprises a metal base, a metal upper cover, a tail fiber, an output end cap and a heat conducting substrate;

The metal base and the metal upper cover form a space for placing the tail fiber and the output end cap, and the tail fiber and the output end cap are both arranged on the metal base;

The coating layer of the tail fiber close to the tail fiber hole site is provided with ultraviolet light glue for fixing;

the tail fiber is provided with a bare fiber corrosion area and a bare fiber dispensing area in sequence towards the direction of the output end cap, a heat conducting substrate is arranged below the bare fiber dispensing area, and high-refractive-index ultraviolet optical glue is filled between the bare fiber dispensing area and the heat conducting substrate;

And fixing the side surface of the thin column body of the output end cap by ultraviolet light glue dispensing.

In a further scheme, the output end cap is a section of quartz round rod with a step radius in the axial direction, the end faces at two sides are coated according to the laser wavelength, the end face of a thin column body of the output end cap is welded with the tail fiber, and laser is emitted from the end face of a thick column body of the output end cap.

In a further scheme, the bare fiber corrosion area is stripped by a first-stage pump, the cladding waveguide structure is destroyed by chemical corrosion, and heat is absorbed and dissipated by the metal base and the metal upper cover.

Further, the bare fiber corrosion area is corroded by chemical corrosive agent.

Still further, the chemical etchant is hydrofluoric acid or a scrub.

Still further, the thermally conductive substrate is a sapphire or glass wafer.

In a further scheme, the tail fiber hole is positioned on the metal upper cover, and the heat conducting substrate is arranged in the groove of the metal base.

The metal base is provided with a groove which is matched with the output end cap and the heat conducting substrate, and a fixing screw hole which is matched with the metal upper cover for positioning.

The invention also provides a method for manufacturing the fiber laser output head with the pump stripping and mode filtering functions, which comprises the following steps:

s1, passing a tail fiber through a tail fiber hole site and then welding the tail fiber with an output end cap;

S2, smearing the polishing paste on the bare fiber corrosion area to perform fiber cladding corrosion, and sequentially arranging the bare fiber corrosion area and the bare fiber dispensing area on the tail fiber towards the direction of the output end cap;

s3, mounting a heat conducting substrate on the metal base;

s4, mounting the output end cap and the tail fiber which are subjected to corrosion treatment in the step S2 on a metal base, and dispensing and fixing a coating layer of the tail fiber and the side surface of a thin column body of the output end cap, which are close to a hole site of the tail fiber, by ultraviolet light glue for fixing;

s5, filling high-refractive-index ultraviolet light glue between the right lower part of the bare fiber dispensing area and the right upper part of the heat conducting substrate;

and S6, covering a metal upper cover, positioning and locking through a fixed screw hole, and sealing and fixing the tail fiber hole position by using optical glue.

The invention has the beneficial effects that:

the invention can shorten the tail fiber length of the passive device positioned behind the gain fiber, reduce nonlinear effect and external disturbance caused by the tail fiber length, improve the degradation results of output characteristics of the fiber laser such as power, pulse width, spectrum width, beam quality and the like;

The output end cap is used for emitting laser;

The bare fiber corrosion area is used for stripping the first-stage pump, and the cladding waveguide structure is destroyed by chemical corrosion, so that most cladding pump light and high-order mode scattering can be leaked, and the metal base and the metal upper cover absorb and dissipate heat;

The bare fiber dispensing area is used for stripping a second stage of pumping, and the high-refractive-index ultraviolet optical glue is used for destroying the refractive index gradient of the waveguide, so that the residual cladding pumping light and the high-order mode are further scattered and leaked into the colloid, the stripping efficiency is improved, and the beam quality is optimized;

The high-refractive-index ultraviolet light glue is filled between the bare fiber dispensing area and the heat conducting substrate, and the good light transmittance and heat conductivity of the heat conducting substrate are utilized to reduce the heat dissipation pressure of the colloid;

The heat conducting substrate is used for heat dissipation of the second-stage pumping stripping, so that risks caused by poor heat conductivity of the ultraviolet light glue with high refractive index are reduced;

The stripping efficiency is improved on the existing traditional CPS product by improving the cladding pumping stripping process and adopting a chemical corrosion and optical glue compound stripping mode;

The output end cap is integrated with the tail fiber, so that the length of the passive fiber after the gain fiber is shortened, nonlinear effect suppression and disturbance suppression are realized, and the output characteristic degradation of the fiber laser power, pulse width, spectrum width, beam quality and the like caused by the nonlinear effect suppression and disturbance suppression can be improved;

compared with the traditional separation type device, the invention has the advantages of high stripping efficiency, compact optical path structure and the like, and can be used in the fields of laser miniaturization and the like.

CPS and the output end cap are closely packaged at the same height, so that nonlinear effect suppression and disturbance suppression of fiber laser output are realized.

Drawings

The invention will be further described with reference to the accompanying drawings and examples, in which:

FIG. 1 is a schematic cross-sectional view of a package of a fiber laser output head including pump stripping and mode filtering functions;

FIG. 2 is a schematic top view of a package of a fiber laser output head including pump stripping and mode filtering functions;

In the figure, 1, a tail fiber, 2, an output end cap, 3, a bare fiber corrosion area, 4, a metal base, 5, a heat conducting substrate, 6, ultraviolet optical glue for fixing, 7, ultraviolet optical glue with high refractive index, 8, a bare fiber dispensing area, 9, a metal upper cover, 10, a fixing screw hole and 11 tail fiber hole sites.

Detailed Description

The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.

Referring to fig. 1 and 2, a fiber laser output head including pump stripping and mode filtering functions comprises a metal base 4, a metal upper cover 9, a pigtail 1, an output end cap 2 and a heat conducting substrate 5. The metal base 4 and the metal upper cover 9 are respectively provided with a fixed screw hole 10, and are fixed through bolts, and the metal base 4 and the metal upper cover 9 form a space for placing the tail fiber 1 and the output end cap 2. The tail fiber 1 and the output end cap 2 are arranged on the metal base 4, a tail fiber hole site 11 is arranged at one end of the space (on the metal upper cover 9), the output end cap 2 is arranged at the other end of the space (the output end cap 2 is arranged on a groove of the metal base 4), the tail fiber 1 passes through the tail fiber hole site 11 and is welded with a thin column of the output end cap 2, and the fiber core of the tail fiber 1 and the optical axis of the output end cap 2 are positioned on the same horizontal plane. The coating layer of the tail fiber 1 near the tail fiber hole position 11 is provided with ultraviolet optical glue 6 for fixing, a bare fiber corrosion area 3 and a bare fiber dispensing area 8 are sequentially arranged on the tail fiber 1 towards the direction of the output end cap 2, a heat conducting substrate 5 is arranged below the bare fiber dispensing area 8, the heat conducting substrate 5 is arranged on a groove of the metal base 4, and high-refractive-index ultraviolet optical glue 7 is filled between the bare fiber dispensing area 8 and the heat conducting substrate 5. The side surface of the thin column body of the output end cap 2 is fixed by ultraviolet light glue 6.

The output end cap 2 is a section of quartz round rod with a step radius in the axial direction, the end faces at two sides are coated according to the laser wavelength, the thin column end face of the output end cap 2 is welded with the tail fiber, and the thick column end face of the output end cap emits laser. The bare fiber corrosion area 3 is stripped by a first-stage pump, the cladding waveguide structure is destroyed by chemical corrosion, and heat dissipation is absorbed by the metal base 4 and the metal upper cover 9. The bare fiber corrosion area 3 is corroded by chemical corrosives such as hydrofluoric acid or frosting paste. The thermally conductive substrate 5 is a sapphire or glass wafer.

Specific examples:

The fiber laser output head is 1064nm fiber laser output head. The tail fiber 1 is nufern/250 passive optical fiber. The diameter of the thin column body of the output end cap 2 is 1mm, and the length is 5mm; the diameter of the thick column body is 2mm, the length is 5mm, and the end faces of the two sides are plated with 1064nm antireflection films. The length of the bare fiber corrosion area is 40mm, the corrosion duration is 35min, and the bare fiber is completely sprayed with deionized water. The metal base 4 is an aluminum alloy base. The heat conductive substrate 5 is a sapphire heat conductive substrate. The dispensing area of the bare fiber dispensing area 8 is 20mm long. The ultraviolet optical glue 6 for fixing is ultraviolet optical glue DSMDF for fixing 0016. The high refractive index ultraviolet optical glue 7 is high refractive index ultraviolet optical glue NOA83H.

A method of making the 1064nm fiber laser output head described above including pump stripping and mode filtering functions, the method comprising the steps of:

S1, enabling a tail fiber 1 containing a bare fiber part with a proper length to pass through a tail fiber hole site 11 and then be welded with an output end cap 2;

S2, smearing the polishing paste ArmourEtch on the tail fiber 1 to perform fiber cladding corrosion, so that a bare fiber corrosion area 3 and a bare fiber dispensing area 8 are sequentially arranged on the tail fiber 1 towards the direction of the output end cap 2;

s3, mounting a heat conducting substrate 5 on the metal base 4;

S4, mounting the output end cap 2 and the tail fiber 1 which are subjected to corrosion treatment in the step S2 on a metal base 4, and fixing a coating layer of the tail fiber 1 close to a tail fiber hole position 11 and a thin column side surface of the output end cap 2 by fixing ultraviolet light glue 6;

s5, filling high-refractive-index ultraviolet light glue 7 between the right lower part of the bare fiber dispensing area 8 and the right upper part of the heat conducting substrate 5;

and S6, covering a metal upper cover 9, positioning and locking through a fixing screw hole 10, and sealing and fixing the tail fiber hole position 11 by using optical glue.

It will be understood that modifications and variations will be apparent to those skilled in the art from the foregoing description, and it is intended that all such modifications and variations be included within the scope of the following claims.

Claims

1. The fiber laser output head comprising the pump stripping and mode filtering functions is characterized by comprising a metal base, a metal upper cover, a tail fiber, an output end cap and a heat conducting substrate;

The metal base and the metal upper cover form a space for placing the tail fiber and the output end cap, and the tail fiber and the output end cap are both arranged on the metal base; one end of the space is provided with a tail fiber hole position, and an output end cap is arranged at the other end of the space; the tail fiber passes through the tail fiber hole site and is welded with the thin column of the output end cap, the fiber core of the tail fiber and the optical axis of the output end cap are positioned on the same horizontal plane, the output end cap is a section of quartz round rod with step radius in the axial direction, the end faces at two sides are coated with films according to the laser wavelength, the thin column end face of the output end cap is welded with the tail fiber, and the thick column end face of the output end cap emits laser;

the optical fiber coupler comprises a tail fiber, a metal base, a metal upper cover, a metal base, a metal tail fiber, a bare fiber corrosion area, a bare fiber dispensing area, a heat conducting substrate, high-refractive-index ultraviolet optical glue, a first-stage pump stripping and heat dissipation, wherein the bare fiber corrosion area and the bare fiber dispensing area are sequentially arranged on the tail fiber towards the direction of an output end cap;

2. The fiber laser output head comprising pump stripping and mode filtering functions of claim 1, wherein the chemical etchant used for chemical etching is hydrofluoric acid or scrub.

3. The fiber laser output head comprising pump stripping and mode filtering functions of claim 1, wherein the thermally conductive substrate is a sapphire or glass wafer.

4. The fiber laser output head including pump stripping and mode filtering functions of claim 1, wherein the pigtail hole is positioned on the metal upper cover, and the heat conducting substrate is arranged in the groove of the metal base.

5. A method of making a fiber laser output head including pump stripping and mode filtering functions as claimed in any one of claims 1-4, comprising the steps of:

s3, mounting a heat conducting substrate on the metal base;