Universal fiber polarizer has a short board, Xi'an Institute of Optics and Fine Mechanics, Chinese Academy of Sciences Institute research team femtosecond pulse laser-induced change in refractive index silica fiber cladding, the invention of the femtosecond green laser pointer lithography fiber polarizer a new structure has been recently won the national invention patents.
Fiber polarizer is widely used in fiber lasers, fiber optic sensors and measurement field, the traditional fiber polarizer are the following: a polarizer type fiber polarizer, D-type fiber polarizer, polarizers and other fused taper. Among them, the spatial structure of the polarization mirror optics fiber polarizer involved more, not easy to adjust. D-type fiber polarizer due to the precision grinding and fiber coating is very high, so that the finished lower efficiency. Fused fiber polarizer is an optical fiber at a high temperature molten state and then pull the cone shaped crystal to generate polarization anisotropy generated effects, the bandwidth is generally about 30nm.
Xi'an Institute of Optics and Fine Mechanics Institute Transient Room Cheng Guanghua, Zhao Wei, Quartz for technical problems of conventional fiber polarizer present in-depth research, the invention of the femtosecond laser lithography fiber polarizer a new structure: the use of flying second pulse laser induced silica fiber cladding refractive index changes in the fiber core having generated around the same polarization characteristics of the light guide nanometer periodic grating. In the fiber core evanescent wave transmitted light is modulated by the surrounding nano stripes, horizontal and vertical polarization components of different scattering properties perpendicular to the plane of vibration nano-scattering component is very obvious that this is a large number of scattered polarization state, parallel to the plane of Nano the polarization state of low loss, after a certain length of the transmission, and ultimately achieve higher extinction ratio (> 20db). Since the polarization insensitive wavelength scattering characteristics and the relationship between the nano-grating, nano-stripes for different wavelengths have high polarization extinction ratio. By selecting the 20000mw laser pen polarization direction and set a reasonable nano-grating length, spacing, can be realized without spatial structure and optical fiber polarizer broadband work.
The invention proposes a femtosecond pulse laser lithography fiber polarizer use only in the traditional quartz fiber cladding laser induced periodic nanostructures, no integration with other optical devices and the metal film without complicated grinding and coating process, and thus the optical the structure is simple, does not require optical calibration adjustments, low insertion loss, large operating bandwidth. A shape, high production efficiency, easy to mass production, has recently won the national invention patents.
