Device and method for inscribing fiber period adjustable fiber grating

Abstract

The invention discloses a device and method inscribing a fiber period adjustable fiber grating. A laser, a beam expander, a convergent lens, a semi-transparent and semi-reflective mirror, a reflector, a Fourier lens, a cylindrical mirror and the like are adopted to form a transverse shear Sagnac interference fiber grating inscribing light path, a linear interference pattern high in contrast ratio and adjustable in period is obtained and acted on a fiber core of a fiber (or other guided wave materials), and the grating is inscribed. The period of the inscribed grating can be continuously changed online by adjusting the transverse shear amount of a Sagnac interferometer, and the inscribing of the period adjustable fiber grating is achieved. Fine adjustment of the shear amount of the interferometer is achieved through a micro displacement platform, and the needed any grating period can be obtained according to an equation. The light path is adjusted easily, the requirement for the coherence of a laser light source is low, the stripe contrast ratio is high, stability is good, the grating period can be continuously adjusted online, and the problems that in an existing mask plate grating inscribing scheme, the cost for replacing a mask plate is high, and the light path is adjusted complexly are solved.

Description

technical field [0001] The invention belongs to the field of preparation of optical fiber micro-nano devices, and relates to a device and method for writing period-tunable optical fiber gratings, in particular to a method for preparing period-tunable gratings inside an optical fiber with a common optical path and low cost using Sagnac interferometer transverse shearing technology method and device thereof. Background technique [0002] Fiber Bragg grating is a structure with periodic modulation of the refractive index of the fiber core, which reflects the incident light whose wavelength satisfies the Bragg condition. The current manufacturing techniques of fiber Bragg gratings mainly include phase mask method, point-by-point writing method, double-beam interferometry and so on. The writing light sources used include ultraviolet continuous laser, ultraviolet pulse laser, infrared pulse laser and the like. The phase mask method has the characteristics of stability and repeat...

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is to provide a device and method for writing period-tunable fiber gratings by overcoming the problems of high cost for preparing fiber gratings with different periods, complex optical path adjustment, high requirements for laser coherence, and limited contrast of grating stripes. , can obtain fiber gratings with uniform stripes, high contrast, and online continuous adjustable period

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