Tunable phase shift fiber grating based on fiber bragg grating and reflecting mirror

Abstract

The invention provides a tunable phase shift fiber grating based on a fiber bragg grating and a reflecting mirror, and relates to a phase shift fiber grating. The invention provides a tunable phase shift fiber grating based on a fiber bragg grating and a reflecting mirror, which has the advantages of narrow transmission peak line breadth, quick tuning, simple structure, high stability, low cost and the like, and can realize bandpass filtering in a transmission mode and effectively inhibit the out-of-band wavelength transmission power of the FBG. The tunable phase shift fiber grating comprises a single mode fiber provided with the fiber bragg grating, a single mode fiber of which one end is plated with the reflecting mirror, a sleeve and piezoelectric ceramics, wherein the single mode fiber provided with the fiber bragg grating and the single mode fiber of which one end is plated with the reflecting mirror are inserted in the sleeve, and a gap is reserved between the single mode fiber provided with the fiber bragg grating and the single mode fiber of which one end is plated with the reflecting mirror; one end of the single mode fiber of which one end is plated with the reflecting mirror and one end of the sleeve are fixed on the piezoelectric ceramics; and the piezoelectric ceramics can be controlled by current to tune the length of the gap, so that the aim of tuning the position of the transmission peak can be achieved by tuning the phase shift.

Description

technical field [0001] The invention relates to a phase-shifting fiber grating, in particular to an adjustable phase-shifting fiber grating based on a fiber Bragg grating and a reflection mirror. Background technique [0002] Phase-shifted Fiber Bragg Grating (Phase-shifted Fiber Bragg Grating, PS-FBG), refers to the introduction of additional phase shift in some way at the center of the geometric length of the uniform Bragg grating, if the introduced phase shift can make a certain When the light of one wavelength changes from interference destructive to enhanced, a very narrow passband will appear in the stopband of the original transmission spectrum under the condition that the reflectivity of the fiber grating is high enough. It can be regarded as a high-fineness bandpass filter in the grating stop band wavelength range. Phase-shifted gratings are written directly with phase masks ([1] Kash Yap, R., Mckee.P.F., and Armes, D., "UV written reflection grating structures inp...

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Problems solved by technology

But this kind of PS-FBG must be accurately truncated at the center of the uniform Bragg grating to have better transmission characteristics, and the Bragg grating is easily damaged during the cutting process

In addition, the line width of the phase-shift grating fabricated by the above-mentioned methods is not narrow enough, and the transmission peak power is lower than the power outside the stop band of the grating transmission spectrum, which limits its application in tunable lasers and band-pass filters

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