CN213717242U

CN213717242U - Novel fiber laser

Info

Publication number: CN213717242U
Application number: CN202023194795.4U
Authority: CN
Inventors: 赵坡; 于振华; 廉昊童; 陈延振
Original assignee: Beijing Oriental Sharp Laser Technology Co ltd
Current assignee: Beijing Oriental Sharp Laser Technology Co ltd
Priority date: 2020-12-25
Filing date: 2020-12-25
Publication date: 2021-07-16
Anticipated expiration: 2030-12-25

Abstract

The utility model provides a novel fiber laser for it is longer to solve the required gain medium length of fiber laser, and electro-optic conversion efficiency is lower, can't further promote the sexual valence ratio of laser and the not high problem of stability. The first beam combiner and the second beam combiner in the novel fiber laser are both (n +1) multiplied by 1 beam combiners, and are provided with n pumping input fibers and a central main fiber; the pump source is connected with the pump input optical fiber of the first beam combiner through a tail fiber, and the central main optical fiber of the output end of the first beam combiner is connected with the central main optical fiber of the input end of the second beam combiner; the pump optical fibers at the input end of the second beam combiner are connected in pairs, and the central main optical fiber, the low-reflection grating, the gain optical fiber, the high-reflection grating and the reflector at the output end of the second beam combiner are sequentially connected; the central main optical fiber at the input end of the first beam combiner is connected with the output device. The utility model discloses simple structure is ingenious, and the stable performance can promote electro-optic conversion efficiency, reduces the laser instrument cost by a wide margin.

Description

Novel fiber laser

Technical Field

The utility model belongs to the technical field of the laser instrument, in particular to novel fiber laser.

Background

The fiber laser belongs to a novel laser, and the rare earth ion doped fiber serves as a gain medium of the laser, has high-quality light beam quality, and has the advantages of good heat dissipation, high reliability, high stability, small size and the like, and is known as a typical representative of the third-generation laser technology. At present, fiber lasers have been widely used in manufacturing, aerospace, chemical engineering, military and other fields.

The fiber laser provided in the prior art is generally shown in fig. 5, and includes a pumping device and a resonant cavity, wherein a pumping light generated by the pumping device pumps a gain fiber in the resonant cavity to generate a laser and output the laser, and since the absorption of the gain fiber to the pumping light is proportional absorption (assuming that the absorption coefficient of the gain fiber to the pumping light is 3dB/m, i.e., 50% of the absorption of the pumping light can be realized by 1 meter of the gain fiber), the fiber laser with the structure has the advantages of long length of a gain medium, low electro-optic conversion efficiency, incapability of further improving the cost performance of the laser, processing of the residual pumping light, and reduction of the stability of the whole fiber during the processing.

Based on the development requirements of low cost, high efficiency and other factors, the invention provides a novel optical fiber laser, and the method can improve the electro-optic conversion efficiency and greatly reduce the cost of the optical fiber laser without introducing a complex structure.

SUMMERY OF THE UTILITY MODEL

In order to solve the gain medium length of fiber laser longer, electro-optic conversion efficiency is lower, can't further promote the price/performance ratio of laser to and surplus pump light need handle, the processing procedure has reduced the problem of the stability of complete machine, utility model provides a novel fiber laser, simple structure is ingenious, and the stable performance can promote electro-optic conversion efficiency, reduces the laser cost by a wide margin.

In order to realize the purpose, the utility model discloses a technical scheme as follows:

the utility model provides a novel optical fiber laser, which comprises a pumping source with a tail fiber, a first beam combiner, a second beam combiner, a low-reflection grating, a gain fiber, a high-reflection grating, a reflector and an output device; the first beam combiner and the second beam combiner are both (n +1) x 1 beam combiners, and are both provided with n pumping input optical fibers and a central main optical fiber; the pump source is connected with the pump input optical fiber of the first beam combiner through the tail optical fiber, and the central main optical fiber at the output end of the first beam combiner is connected with the central main optical fiber at the input end of the second beam combiner; the pumping optical fibers at the input end of the second beam combiner are connected in pairs, and the central main optical fiber, the low-reflection grating, the gain optical fiber, the high-reflection grating and the reflector at the output end of the second beam combiner are sequentially connected; and the central main optical fiber at the input end of the first beam combiner is connected with the output device.

Preferably, the gain fiber is a rare earth doped fiber.

Preferably, the rare earth doped fiber is an ytterbium doped fiber.

Preferably, the high reflective grating is a high reverse bragg fiber grating, and the low reverse grating is a low reverse bragg fiber grating.

Preferably, the pump source is a laser diode.

Preferably, the output device is a QBH output head.

The utility model discloses following beneficial effect has:

the utility model provides a novel fiber laser, low anti-grating, high anti-grating, gain fiber constitute the laser resonator, after the pumping light gets into the resonator cladding and absorbs, laser is produced in the fibre core of resonator, exports via the fibre core of low reflection grating, behind the fibre core transmission of second beam combiner, first beam combiner, exports via output device; and pumping light provided by the pumping source enters the cladding through the first beam combiner and then enters the cladding of the resonant cavity for primary absorption, the unabsorbed pumping light returns to the resonant cavity for secondary absorption after passing through the reflector, the rest pumping light returns to the resonant cavity after passing through the input pumping optical fiber of the second beam combiner for third absorption, and the step is repeated until the pumping light is completely absorbed and is completely converted into laser output. For example, the absorption coefficient of the gain fiber is 0.5dB/m, in order to realize 12dB effective absorption, the original light path needs 24m gain fiber, and the novel fiber laser can reduce the expensive gain fiber to 12m by means of the characteristic of repeated cyclic absorption, thereby greatly reducing the cost of the whole fiber laser.

The utility model has simple and smart structure and stable performance, can greatly shorten the gain optical fiber and reduce the cost of the whole machine; the residual pump light does not need additional process treatment, so that the stability of the whole machine is improved; the electro-optical conversion efficiency is high.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a novel optical fiber laser according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a pump light path according to an embodiment of the present invention;

fig. 3 is a schematic diagram of a laser route according to an embodiment of the present invention;

FIG. 4 is a schematic view of the interior of an optical fiber;

fig. 5 is a schematic diagram of a conventional fiber laser structure.

Description of reference numerals:

1. a mirror; 2. high-reflection grating; 3. a gain fiber; 4. a low-reflection grating; 5. a second combiner; 6. a first combiner; 7. a pump source; 71. tail fiber; 8. an output device; 11. a fiber core; 22. an inner cladding; 33. an outer cladding; 44. a coating layer; 55. laser; 66. pump light; 101. a conventional fiber laser pumping dumping device; 102. high-reflection grating of traditional fiber laser; 103. a conventional fiber laser gain fiber; 104. the traditional fiber laser low-reflection grating; 105. a conventional fiber laser combiner; 106. a conventional fiber laser pump source; 107. a traditional fiber laser output device.

Detailed Description

In order to make the technical solution of the present invention better understood by those skilled in the art, the present invention will be described in detail with reference to the accompanying drawings and specific embodiments.

The present embodiment provides a novel fiber laser, as shown in fig. 1-3, the novel fiber laser is a backward pumping structure, and includes a pumping source 7 with a tail fiber 71, a first beam combiner 6, a second beam combiner 5, a low reflective grating 4, a gain fiber 3, a high reflective grating 2, a reflector 1, and an output device 8; the first beam combiner 6 and the second beam combiner 5 are both (n +1) × 1 beam combiners, and the first beam combiner 6 and the second beam combiner 5 are both provided with n pumping input optical fibers and a central main optical fiber; the pump source 7 is connected with the pump input optical fiber of the first beam combiner 6 through the pigtail 71, and the central main optical fiber at the output end of the first beam combiner 6 is connected with the central main optical fiber at the input end of the second beam combiner 5; the pump optical fibers at the input end of the second beam combiner 5 are connected in pairs, and the central main optical fiber at the output end of the second beam combiner 5, the low reflective grating 4, the gain optical fiber 3, the high reflective grating 2 and the reflector 1 are connected in sequence; the central main optical fiber at the input end of the first beam combiner 6 is connected with the output device 8.

The gain optical fiber 3 is a rare earth doped optical fiber, and the rare earth doped optical fiber is an ytterbium doped optical fiber; the high reflecting grating 2 is a high reverse Bragg fiber grating, and the low reflecting grating 4 is a low reverse Bragg fiber grating; the pumping source 7 is a laser diode; the output device 8 is a QBH output head.

Most of the existing optical fibers are of a double-clad structure, as shown in fig. 4, the fiber core 11, the inner cladding 22, the outer cladding 33 and the coating layer 44 are sequentially arranged from inside to outside, and the refractive index of the double-clad optical fiber is sequentially reduced from inside to outside based on the basic principle of total reflection, so that the laser 55 can be effectively bound and propagated in each layer, in order to improve the efficiency of effective pumping absorption, the required laser 55 is generally propagated in the fiber core with a small diameter, and the pumping light 66 is propagated in the cladding with a large diameter. The beam combiner adopts the basic principle that the N pumping arms and the central arm are tapered and then welded with another passive optical fiber, namely the N pumping arms are welded to a cladding while the central arm and the fiber core of the passive optical fiber are completely welded, and then the pumping light is guided into a main light path.

The low-reflection grating 4, the high-reflection grating 2 and the gain fiber 3 form a laser resonant cavity, when pump light enters a cladding of the resonant cavity for absorption, laser is generated in a fiber core of the resonant cavity, is output through the fiber core of the low-reflection grating 4, is transmitted through the fiber cores of the second beam combiner 5 and the first beam combiner 6, and is output through the output device 8; and the pumping light provided by the pumping source 7 enters the cladding through the first beam combiner 6, then enters the cladding of the resonant cavity to be absorbed for the first time, the unabsorbed pumping light returns to the resonant cavity to be absorbed for the second time after passing through the reflector 1, the rest pumping light returns to the resonant cavity after passing through the input pumping optical fiber of the second beam combiner 5 to be absorbed for the third time, and the step is repeated until the pumping light is completely absorbed and is completely converted into laser output. For example, the absorption coefficient of the gain fiber is 0.5dB/m, in order to realize 12dB effective absorption, the original light path needs 24m gain fiber, and the novel fiber laser can reduce the expensive gain fiber to 12m by means of the characteristic of repeated cyclic absorption, thereby greatly reducing the cost of the whole fiber laser.

According to the technical scheme, the novel optical fiber laser is simple and ingenious in structure and stable in performance, the gain optical fiber can be greatly shortened, and the cost of the whole optical fiber laser is reduced; the residual pump light does not need additional process treatment, so that the stability of the whole machine is improved; the electro-optical conversion efficiency is high.

The embodiments of the present invention have been described in detail through the embodiments, but the description is only exemplary of the embodiments of the present invention and should not be considered as limiting the scope of the embodiments of the present invention. The scope of protection of the embodiments of the present invention is defined by the claims. All utilize technical scheme of the embodiment of the utility model, or technical staff in the field is in the utility model discloses under embodiment technical scheme's the inspiration the utility model discloses in the essence and the protection scope of the embodiment, design similar technical scheme and reach above-mentioned technological effect, perhaps to the impartial change and improvement etc. that the application scope was made, all should still belong to within the protection scope is covered to the patent of the embodiment of the utility model.

Claims

1. A novel optical fiber laser is characterized by comprising a pumping source (7) with a tail fiber, a first beam combiner (6), a second beam combiner (5), a low-reflection grating (4), a gain fiber (3), a high-reflection grating (2), a reflector (1) and an output device (8); the first beam combiner (6) and the second beam combiner (5) are both (n +1) x 1 beam combiners, and are provided with n pump input optical fibers and a central main optical fiber; the pump source (7) is connected with a pump input optical fiber of the first beam combiner (6) through the tail optical fiber (71), and a central main optical fiber at the output end of the first beam combiner (6) is connected with a central main optical fiber at the input end of the second beam combiner (5); the pump optical fibers at the input end of the second beam combiner (5) are connected in pairs, and the central main optical fiber at the output end of the second beam combiner (5), the low-reflection grating (4), the gain optical fiber (3), the high-reflection grating (2) and the reflector (1) are connected in sequence; and a central main optical fiber at the input end of the first beam combiner (6) is connected with the output device (8).

2. The new fiber laser according to claim 1, characterized in that said gain fiber (3) is a rare earth doped fiber.

3. The novel fiber laser of claim 2, wherein the rare-earth doped fiber is an ytterbium-doped fiber.

4. The new fiber laser according to claim 1, characterized in that said high-reflection grating (2) is a high-reflection bragg fiber grating and said low-reflection grating (4) is a low-reflection bragg fiber grating.

5. The new fiber laser according to claim 1, characterized in that said pump source (7) is a laser diode.

6. The new fiber laser according to claim 1, characterized in that said output means (8) is a QBH output stub.