CN214478413U

CN214478413U - 2-micron-band cylindrical vector optical fiber random laser based on optical fiber random grating

Info

Publication number: CN214478413U
Application number: CN202120881248.9U
Authority: CN
Inventors: 董新永; 莫锦恋; 朱德才; 徐鹏柏; 王云才; 秦玉文
Original assignee: Guangdong University of Technology
Current assignee: Guangdong University of Technology
Priority date: 2021-04-26
Filing date: 2021-04-26
Publication date: 2021-10-22
Anticipated expiration: 2031-04-26

Abstract

The application discloses 2 mu m waveband column vector optical fiber random laser based on optical fiber random grating, thulium-doped optical fiber is used as a gain medium of the laser, optical random grating is used for providing optical random distribution feedback, and partial fundamental mode light is converted into LP (low-pass) light by an optical mode converter₁₁The cylindrical vector light of the mode realizes high proportion reflection and LP of the fundamental mode light by using few-mode fiber grating₁₁And (3) the mode light is transmitted completely, so that the cylindrical vector random laser output of a 2 mu m wave band is realized.

Description

2-micron-band cylindrical vector optical fiber random laser based on optical fiber random grating

Technical Field

The application relates to the technical field of lasers, in particular to a 2 mu m waveband column vector optical fiber random laser based on an optical fiber random grating.

Background

The laser with the wave band of 2 mu m has important application value and irreplaceable effect in a plurality of fields such as optical communication, medical treatment, military affairs and the like.

The fiber random laser is different from a common fiber laser in that the resonant cavity has no fixed cavity length, has the advantages of low coherence, simple structure, simple maintenance and the like, and can be applied to the field of microscopic imaging.

The fiber random laser can be classified into a rayleigh scattering distribution feedback type, a filling type and a fiber random grating feedback type according to the difference of the feedback types. The fiber random laser based on the fiber random grating feedback forms random distribution optical feedback by randomly writing the fiber grating on the fiber, and has the advantages of lower threshold power, shorter required fiber length and the like compared with other feedback type fiber random lasers.

In addition, the column vector light is different from the Gaussian beam, the electric field intensity is distributed in a circular ring shape, and the column vector light has a unique focusing characteristic. The fiber column vector light laser generally adopts an LP11 mode in an optical fiber, and has important application value in the fields of surface plasma excitation, laser processing, microscopic imaging and the like.

The 2 mu m waveband fiber laser, the fiber random laser and the fiber column vector light laser are different directions of the fiber laser research, the advantages of the three lasers are different, but the 2 mu m waveband column vector light random fiber laser is not reported at present.

Chinese utility model patent publication No. CN108539567A discloses a phase shift grating-based 2 μm waveband tunable random fiber laser, which utilizes a phase shift grating to form randomly distributed optical feedback, and utilizes thulium-doped fiber as a gain medium to realize output of 2 μm waveband random laser, but the 2 μm waveband random laser is not cylindrical vector light.

Chinese utility model patent publication No. CN107872002A discloses a high efficiency all-fiber column vector beam laser, which utilizes a few-mode long period fiber grating to have high mode conversion efficiency and low insertion loss characteristic at resonance wavelength, realizes high efficiency mode conversion by introducing the few-mode long period fiber grating in the laser cavity, reduces the loss in the cavity, realizes high efficiency output of column vector laser beam, but this column vector beam is not random laser.

In addition, some papers disclose that a resonant cavity is formed by using a fiber ring mirror and few-mode fiber gratings, and erbium-doped fibers are used as gain media. Adopting a long-period fiber grating to excite a high-order mode to realize the output of 1550nm column vector light beams, wherein the column vector light beams are not random laser; also, a paper discloses that a resonant cavity is formed by using fiber bragg gratings and few-mode fiber gratings, ytterbium-doped fibers are used as gain media, a high-order mode is excited by adopting a dislocation welding point, and the output of 1053nm column vector beams is realized, but the column vector beams are not random lasers.

Therefore, the current technology only outputs 2 μm band random laser light or cylindrical vector light, but does not simultaneously output 2 μm band cylindrical vector random laser light.

SUMMERY OF THE UTILITY MODEL

The application provides a 2 mu m waveband cylindrical vector optical fiber random laser based on an optical fiber random grating, which is used for solving the technical problem that the prior art can only output 2 mu m waveband random laser or cylindrical vector light.

In view of the above, the present application provides a 2 μm band column vector fiber random laser based on a fiber random grating, comprising: the optical fiber coupler comprises a first optical fiber joint, an optical fiber random grating, a pump laser, a wavelength division multiplexer, a thulium-doped optical fiber, a mode converter, a few-mode optical fiber grating and a second optical fiber joint;

first optical fiber splice with the first end of the random grating of optic fibre is connected, the second end of the random grating of optic fibre with wavelength division multiplexer's first input end is connected, the pump laser is used for producing the pump light, the pump laser with wavelength division multiplexer's second input end is connected, wavelength division multiplexer's output with the first end of mixing thulium optic fibre is connected, mix thulium optic fibre the second end with mode converter's first end is connected, mode converter's second end with the first end of few mode optic fibre is connected, few mode fiber grating writes on the few mode optic fibre, the second end of few mode optic fibre with second optical fiber splice connects.

Preferably, the first and second fibre optic splices are FC/APC splices.

Preferably, the fiber random grating is a periodic grating or a fiber grating with randomly distributed intervals between adjacent gratings.

Preferably, the pump laser is a semiconductor laser diode or a fiber laser, and the output wavelength of the laser generated by the pump laser is within the absorption band of the thulium-doped fiber.

Preferably, the fundamental mode reflection wavelength of the few-mode fiber grating is within a 2 μm band.

According to the technical scheme, the utility model has the advantages of it is following:

the utility model provides a 2 mu m wave band post vector optic fibre random laser based on optic fibre random grating realizes random distribution optical feedback through utilizing optic fibre random grating, adopts thulium-doped optic fibre to amplify as gain medium to light, reduces laser instrument threshold power, turns into the high order mode through the partial fundamental mode of mode converter transmission in with optic fibre, through few mode fiber grating transmission fundamental mode, and then realizes exporting the 2 mu m wave band post vector random laser of high efficiency conversion.

Drawings

Fig. 1 is a schematic structural diagram of a 2 μm band column vector fiber random laser based on a fiber random grating according to an embodiment of the present application.

Detailed Description

In order to make the technical solutions of the present application better understood, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

For easy understanding, please refer to fig. 1, the present application provides a 2 μm band cylindrical vector fiber random laser based on a fiber random grating, comprising: the optical fiber laser device comprises a first optical fiber connector 1, an optical fiber random grating 2, a pumping laser 3, a wavelength division multiplexer 4, a thulium-doped optical fiber 5, a mode converter 6, a few-mode optical fiber 7, a few-mode optical fiber grating 8 and a second optical fiber connector 9;

the first optical fiber connector 1 is connected with a first end of the optical fiber random grating 2, a second end of the optical fiber random grating 2 is connected with a first input end of the wavelength division multiplexer 4, the pump laser 3 is used for generating pump light, the pump laser 3 is connected with a second input end of the wavelength division multiplexer 4, an output end of the wavelength division multiplexer 4 is connected with a first end of the thulium-doped optical fiber 5, a second end of the thulium-doped optical fiber 5 is connected with a first end of the mode converter 6, a second end of the mode converter 6 is connected with a first end of the few-mode optical fiber 7, the few-mode optical fiber grating 8 is inscribed on the few-mode optical fiber 7, and a second end of the few-mode optical fiber 7 is connected with a second optical fiber connector 9.

The working principle of the embodiment is as follows:

the fiber random grating 2 and the few-mode fiber grating 8 form random light feedback, and feedback light oscillates back and forth between the fiber random grating 2 and the few-mode fiber grating 8 to obtain random laser; the pump laser 3 generates pump light, the pump light is transmitted to the wavelength division multiplexer 4, the pump light is coupled to a light path through the wavelength division multiplexer 4, the pump light is transmitted to the thulium-doped optical fiber 5 after passing through the wavelength division multiplexer 4, the thulium-doped optical fiber 5 is used as a gain medium, the light is amplified under the excitation of the pump laser 3, a part of basic modes transmitted in the light path are converted into high-order (LP11) modes through the mode converter 6, other unconverted basic modes in the light path are reflected through the few-mode fiber grating 8, and therefore the effect of filtering the basic modes is achieved.

Further, the first and second optical fiber splices 1 and 9 are FC/APC splices for eliminating fresnel reflection.

Further, the fiber random grating 2 is a periodic grating or a fiber grating in which intervals between adjacent gratings are randomly distributed.

In a typical example, the fiber random grating 2 is fabricated on a single mode fiber.

Further, the pump laser 3 is embodied as a semiconductor laser diode or a fiber laser, and the output wavelength of the laser generated by the pump laser 3 is within the absorption band of the thulium doped fiber 5.

Further, the fundamental mode reflection wavelength of the few-mode fiber grating 8 is within the 2 μm band.

It should be noted that in this embodiment, the optical fiber random grating 2 is used to realize randomly distributed optical feedback, the thulium-doped optical fiber 5 is used as a gain medium to amplify light, so as to reduce the threshold power of the laser, generate 2 μm-band random laser, convert part of the fundamental mode transmitted in the optical fiber into a high-order mode through the mode converter 6, and emit the fundamental mode through the few-mode optical fiber grating 8, thereby realizing output of the 2 μm-band cylindrical vector random laser with high efficiency conversion.

In another embodiment, random laser light is generated using random rayleigh scattering grating feedback, but the required fiber length is longer and the laser threshold power is higher.

The above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.

Claims

1. 2 mu m wave band column vector optical fiber random laser based on optical fiber random grating is characterized by comprising: the optical fiber coupler comprises a first optical fiber joint, an optical fiber random grating, a pump laser, a wavelength division multiplexer, a thulium-doped optical fiber, a mode converter, a few-mode optical fiber grating and a second optical fiber joint;

2. The fiber bragg grating based 2 μ ι η band cylindrical vector fiber optic random laser of claim 1, wherein the first and second fiber splices are FC/APC splices.

3. The fiber random grating-based 2 μm band column vector fiber random laser of claim 1, wherein the fiber random grating is a periodic grating or a fiber grating with randomly distributed spaces between adjacent gratings.

4. The fiber bragg grating-based 2 μm band column vector fiber random laser of claim 1, wherein the pump laser is a semiconductor laser diode or a fiber laser, and an output wavelength of the laser generated by the pump laser is within an absorption band of the thulium-doped fiber.

5. The fiber optic random grating-based 2 μm band column vector fiber random laser of claim 1, wherein the fundamental mode reflection wavelength of the few-mode fiber grating is within the 2 μm band.