All-fiber filter based on thin-core fibers

Abstract

The invention relates to an all-fiber filter based on thin-core fibers. The conventional fiber grating filter has poor temperature stability, and is not suitable for the operation under extreme working conditions. The all-fiber filter comprises a packing box, a single-mode fiber component is arranged by passing through the packing box, and two ends of the single-mode fiber component are connected with a ring flange respectively. The single-mode fiber component comprises three sections of single-mode fibers which are connected in series, wherein the single-mode fibers at two ends adopt standard single-mode fibers, the middle section of the single-mode fibers adopts thin-core single-mode fibers, the three sections of the single-mode fibers are coaxially arranged, and two ends of the thin-core single-mode fibers are fused with one end of the two sections of the standard single-mode fibers respectively. The filter is simple to manufacture, and has good temperature stability and response characteristic to the external refractive index change.

Description

technical field [0001] The invention belongs to the field of optical fiber technology, and relates to an all-fiber filter based on a thin-core optical fiber. Background technique [0002] Due to the advantages of small size, light weight, simple structure, and anti-electromagnetic interference, optical fiber devices have been widely used in communication, sensing and other fields. Especially for the all-fiber filter, its performance is directly related to the transmission quality of the current optical fiber communication network. Among them, fiber grating is the most mature fiber-optic filter in the application today. It is divided into two types: one is called fiber Bragg grating (Fiber BraggGrating, FBG), which is a narrow-band reflective band-pass filter The other is called long period fiber grating (Long Period Fiber Grating, LPG), which is a transmission type band-stop filter. Although the structure of these two filters is relatively simple and the rejection ratio is...

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Problems solved by technology

However, some design schemes often have complicated processes in the production process, such as connecting a small section of multimode fiber, or using heating to expand the fiber core at the end face of the fiber, which increases the difficulty of making the device; some require special Materials, such as the use of some special double-clad fibers, photonic crystal fibers, etc., are quite expensive; and the mechanical strength of some structures is very poor, such as the structure of high-order mode excitation through fiber taper, which has almost no practical value

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