A method for writing apodized fiber gratings

Abstract

The invention discloses an apodization FBG (fiber bragg grating) inscribing system and method, and the system comprises an optical platform, an excimer laser, a reflector group, a diaphragm, a beam-expanding cylindrical lens group, an apodization device, a focusing cylindrical lens, a phase mask template, and an optical fiber clamping device. The apodization device is located between the beam-expanding cylindrical lens group and the focusing cylindrical lens, and also comprises an amplitude mask template with a positive template and a negative template, and a lifting drive assembly disposed on the optical platform, wherein the amplitude mask template is disposed at the lifting end of the lifting drive assembly. The optical fiber clamping device comprises two optical fiber clamping tools and two rotating devices which are disposed on the optical platform and drives the two optical fiber clamping tools to rotate around an optical fiber axis synchronously. The method comprises the steps: setting the parameters of the excimer laser, preparing the optical fibers, and inscribing the apodization FBG. The system can be used for preparing different types of apodization FBGs, can eliminate the light-sensing refractive index modulation asymmetry caused by the large core diameter for the inscribing of the large-core-diameter apodization FBGs, and can prepare high-performance large-core-diameter apodization FBGs.

Description

technical field [0001] The invention relates to the technical field of fiber grating writing, in particular to an apodized fiber grating writing system and method. Background technique [0002] Fiber gratings are widely used in fiber lasers, fiber optic communications, and fiber optic sensing. Compared with traditional gratings, fiber gratings have the advantages of narrow line width, low insertion loss, strong anti-electromagnetic interference, high sensitivity, light weight, small size, easy to achieve wavelength division multiplexing, and flexible use. The all-fiber laser composed of fiber grating instead of the traditional optical dichroic mirror has the advantages of high stability and compact structure, which makes the fiber laser practical. The emergence of fiber gratings has also greatly promoted the development of optical fiber communication and optical fiber sensing. [0003] At present, the main methods for fabricating fiber Bragg gratings are mask method, point...

AI Technical Summary

Problems solved by technology

This writing system is used to make fiber Bragg gratings. Since no apodization device is introduced, the prepared fiber Bragg gratings have serious sidebands in the transmission spectrum and reflection spectrum; and when the optical fiber is a large core fiber, it is limited Controlling precision, the focused beam cannot be accurately placed at the center of the fiber, resulting in an asymmetrical modulation of the fiber core's light-sensitive refractive index in the radial direction

This modulation asymmetry is not conducive to improving the transmission spectrum and reflection spectrum depth of large-core fiber Bragg gratings, and will affect the performance and application of large-core fiber Bragg gratings.

Existing phase mask writing techniques cannot eliminate this modulation asymmetry

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