CN100392453C

CN100392453C - Thermal expanding chip radius microlens optical fibre for coupled big-power semiconductor laser

Info

Publication number: CN100392453C
Application number: CNB2004100252780A
Authority: CN
Inventors: 张全; 沈诗哲
Original assignee: Zhejiang University ZJU
Current assignee: Zhejiang University ZJU
Priority date: 2004-06-10
Filing date: 2004-06-10
Publication date: 2008-06-04
Anticipated expiration: 2024-06-10
Also published as: CN1584653A

Abstract

The present invention discloses a heat expanding core diameter micro-lens optical fiber for coupling high-power semiconductor lasers. The core diameter is expanded in a heating mode at the end head part of a multimode optical fiber; the end head of the heat expanding core diameter part has a wedge-shaped optical fiber end surface, a circular arc surface and a cylindrical optical fiber micro-lens tangential with the wedge-shaped optical fiber end surface. The present invention has the advantages that the multimode optical fiber is carried out simple core diameter heat expansion and the optical fiber grinding technology; the present invention can fabricate micro-lens optical fibers which have high coupling efficiency and high coupling tolerance degree and are used for coupling the high-power semiconductor lasers. Optical fiber coupling high-power semiconductor lasers with compact structure, high coupling efficiency and high brightness can be obtained by selecting heat expanding core diameter micro-lens optical fibers of different core diameters for aiming at the semiconductor lasers in different luminous regions. In addition, simple and convenient encapsulation brought by the simple processing and the high coupling tolerance degree of the heat expanding core diameter micro-lens optical fiber makes the cost of the whole laser coupler reduced. The present invention can be widely used in the fields of pumping of solid lasers, industrial laser processing, optical fiber lasers, etc.

Description

The thermal expanding core path microlens optical fibre of high power semiconductor lasers is used to be coupled

Technical field

The present invention relates to a kind of thermal expanding core path microlens optical fibre of the high power semiconductor lasers that is used to be coupled.Be specially adapted to the important component part of gordian technique optical fiber coupling in the LASER Light Source of the pumping source of pumping source, optical fiber laser pump source, fiber amplifier of solid state laser and industrial processes: the thermal expanding core path lenticule multimode optical fiber of be used to be coupled high-power (1～10 watt) wide light-emitting area (emit field size 50～500 μ m * 1 μ m) semiconductor laser, laser array.

Background technology

High brightness, powerful fiber coupled laser diode can be widely used in pumping, the industrial lasers processing and other fields of solid state laser: by coupling efficiently, can provide the shoot laser of low numerical aperture, high-output power; And, by the coupling of optical fiber, can effectively enlarge the occasion of utilizing of semiconductor laser, as direct and fiber laser coupling etc.

Improve the laser power of optical fiber output, just must improve the power of the semiconductor laser that is coupled; At present, have the semiconductor laser of wide emit field, single-shot light zone can outgoing be up to 8 watts laser, and by adopting the method for laser array and heap, can obtain the emergent power of maximum number hectowatt.But the angle of divergence of the semiconductor laser outgoing beam of wide emit field is bigger, and differs also bigger at slow axis and fast axle two directional divergence angles, is respectively about 10 degree * 40 degree, so difficult to be coupled in the less optical fiber of numerical aperture.

At present, the fiber-optic coupling method of high brightness high power semiconductor laser commonly used is to adopt discrete optical device between laser instrument and optical fiber, and to high-power, the outgoing beam of wide emit field semiconductor laser carries out being coupled in the optical fiber after the shaping.This method can more effective coupled laser.But, owing to adopted discrete optical element, the loss of laser in coupling process strengthened, restricted the raising of coupling efficiency.And the use of discrete component also makes the alignment tolerant degree of device reduce, thereby the cost of assembling calibration is improved.In addition, the cost of manufacture of individual optical elements itself has also further improved the cost of integral coupler spare.

Microlens optical fibre technology development in recent years is rapider.By fusion, draw awl and methods such as grinding, can process lenticule at optic fibre end, and then improve the coupling numerical aperture of optical fiber, the high coupling efficiency of laser is reached more than 90%.This method has been abandoned discrete optical device, has reduced the loss of laser.But for general microlens optical fibre, the optical fiber core diameter must be complementary with the lasing fluorescence zone, can't improve coupling brightness.In addition, because lenticular employing has reduced coupling tolerate degree significantly.Make the difficulty of assembling and calibration also bigger, so cost is also than higher.

Summary of the invention

The thermal expanding core path microlens optical fibre that the purpose of this invention is to provide a kind of high power semiconductor lasers that is used to be coupled.

It is at the multimode optical fiber end portion core diameter to be carried out the heat expansion, and the termination of thermal expanding core path part has the tangent cylindric optical fibre microlens of cuneiform optical fiber end face and arc surface and cuneiform optical fiber end face.

Advantage of the present invention is: by multimode optical fiber being compared expansion of easy core diameter heat and optical fiber lapping PROCESS FOR TREATMENT, can produce the be coupled microlens optical fibre of high power semiconductor lasers of coupling efficiency height (＞90%), high being used to of tolerance.By semiconductor laser at different light-emitting zone sizes, select the thermal expanding core path optical fibre microlens of different core diameters, can obtain the optical fiber-coupled laser device of compact conformation, high coupling efficiency, high brightness.In addition, because the processing of this thermal expanding core path lens fiber is simple, and, the cost of whole laser coupled device is reduced because the encapsulation that raising brought of coupling tolerate degree is easy.Can be widely used in fields such as solid state laser pumping, industrial lasers processing, fiber laser.

Description of drawings

Fig. 1 is used to be coupled the thermal expanding core path microlens optical fibre perspective view of high power semiconductor lasers;

Fig. 2 is used to be coupled the thermal expanding core path microlens optical fibre vertical view of high power semiconductor lasers;

Fig. 3 is used to be coupled the thermal expanding core path microlens optical fibre side sectional view of high power semiconductor lasers;

Fig. 4 is that high power semiconductor lasers and the present invention constitute the coupled system synoptic diagram.

Specific implementation method

The thermal expanding core path microlens optical fibre of high power semiconductor lasers of being used to be coupled is to have thermal expanding core path 204 on multimode optical fiber 101 terminations, and thermal expanding core path has the tangent cylindric optical fibre microlens 103 of cuneiform optical fiber end face 102,306 and arc surface and cuneiform optical fiber end face 102,306.Core diameter after the heat expansion is 1.02～2 times of the preceding core diameter of expansion.The length of thermal expanding core path part is 0.2～20mm.Cuneiform optical fiber end face 102 has the angle of wedge about optical fiber sagittal plane symmetry, and angle of inclined end face 102,306 is 10～160 ° about it.Cylindric lenticule 103 is tangent with cuneiform optical fiber end face 102,306, and its face of cylinder is perpendicular to meridional plane, and face of cylinder radius is less than the core radius of multimode optical fiber 101.Cuneiform optical fiber end face 102,306 and cylindric lenticule 103 surfaces are coated with anti-reflection film.

The present invention at first carries out the processing that core diameter heat is expanded by the end portion to multimode optical fiber 101, effectively expands multimode optical fiber 101 core diameters.The processing of multimode optical fiber thermal expanding core path, principal feature are to the multimode optical fiber that has cut, utilize laser or other local heat source, and heat is concentrated in the fiber end face fiber cores scope, heat by the fiber cores end face to internal divergence.By thermal effect, effectively expand thermal expanding core path 204.

Secondly, method by optical fiber lapping and fusion, going out cuneiform optical fiber end face 102,306 and cylindric optical fibre microlens 103 through multimode optical fiber 101 end machining after the core diameter heat expansion processing, because cuneiform optical fiber end face 102,306 is the plane, the profile of cylindric optical fibre microlens 103 is cylindrical, so process is fairly simple and easy operation.

Coupled system comprises high power semiconductor lasers 407, and the heat of the said high power semiconductor lasers that is used to be coupled expansion microlens optical fibre.Because the heat of the said high power semiconductor lasers that is used to be coupled expansion microlens optical fibre has improved coupling tolerate degree effectively, so alignment request is reduced relatively between laser and the optical fiber, can reach good coupling efficiency by fairly simple adjustment, thereby reach the purpose that reduces cost.In addition, also can improve the luminance brightness of whole optical fiber-coupled laser device by core diameter and the lasing fluorescence zone coupling that allows after overheated expansion.

Claims

1. the thermal expanding core path microlens optical fibre of the high power semiconductor lasers that is used to be coupled, it is characterized in that: have thermal expanding core path part (204) on multimode optical fiber (101) termination, the termination of thermal expanding core path part has cuneiform optical fiber end face (102,306) and arc surface and the tangent cylindric optical fibre microlens (103) of cuneiform optical fiber end face (102,306).

2. the thermal expanding core path microlens optical fibre of a kind of high power semiconductor lasers that is used to be coupled according to claim 1 is characterized in that 1.02～2 times of core diameter before said thermal expanding core path is for expansion.

3. the thermal expanding core path microlens optical fibre of a kind of high power semiconductor lasers that is used to be coupled according to claim 1 is characterized in that said thermal expanding core path length is 0.2～20mm.

4. the thermal expanding core path microlens optical fibre of a kind of high power semiconductor lasers that is used to be coupled according to claim 1, it is characterized in that having the angle of wedge about optical fiber sagittal plane symmetry at said cuneiform optical fiber end face (102), its up and down the angle of inclined end face (102,306) be 10～160 °.

5. the thermal expanding core path microlens optical fibre of a kind of high power semiconductor lasers that is used to be coupled according to claim 1, it is characterized in that at said cylindric lenticule (103) and cuneiform optical fiber end face (102,306) tangent, its face of cylinder is perpendicular to meridional plane, and face of cylinder radius is less than the core radius of multimode optical fiber (101).

6. the thermal expanding core path microlens optical fibre of a kind of high power semiconductor lasers that is used to be coupled according to claim 1 is characterized in that said cuneiform optical fiber end face (102,306) and cylindric lenticule (103) surface are coated with anti-reflection film.