Capacitive-feedback-type tunable Fabry-Perot filter

Abstract

The invention relates to a capacitive-feedback-type tunable Fabry-Perot filter, which comprises two supports arranged oppositely, plane cavity mirrors arranged oppositely on the two supports respectively, and a plurality of piezoelectric ceramics connected with the two supports and uniformly distributed on the outer circumferences of the two plane cavity mirrors. Each support is provided with a light passing hole sharing the same optical axis with the corresponding plane cavity mirror and used for allowing light to be in and out; opposite cavity surfaces of the two plane cavity mirrors are respectively plated by a plurality of metal electrodes to form a plurality of pairs of capacitive sensors; a gap value between the two cavity surfaces can be obtained according to the capacitance of each capacitive sensor; and parallelism of the two cavity surfaces and cavity length between the two cavity surfaces are controlled according to the capacitance of each capacitive sensor. The two plane cavity mirrors are plated by metal films to form a plurality of parallel plate capacitor pairs; and through the capacitance of the capacitors, small included angle between the parallel plates and the gap value of each part can be measured in real time so as to control the parallelism and Fabry-Perot cavity length (output wavelength).

Description

technical field [0001] The invention relates to an optical device used in a spectrum testing and sensing system, in particular to a capacitive feedback type tunable Fabry-Perot filter. Background technique [0002] The scanning Fabry-Perot filter is a tunable optical filter device with a flexible structure, low insertion loss, fast tuning speed, wide tuning range, and high precision, and has been widely valued. In the field of optical communication, scanning Fabry-Perot filters can be used for demultiplexing of wavelength division multiplexing; in the field of optical fiber sensing, they can be used as displacement and strain sensing devices, and can also be used as wavelength demodulation devices for fiber grating sensors. In addition, scanning Fabry-Perot filters also have important applications in the fields of fiber lasers and spectral analysis. In terms of spectroscopic instruments, there is currently a Fabry-Perot cavity scanning filter method to achieve spectral reso...

AI Technical Summary

Problems solved by technology

[0009] Aiming at the problem that the existing methods are difficult to measure and actively control the parallelism and cavity length of parallel plane cavities, a capacitive feedback type tunable Fabry-Perot filter is proposed, by plating metal on two plane cavity mirrors The film constitutes a plurality of parallel plate capacitor pairs, and the capacitance value of these capacitors can be used to measure the small angle between the parallel plates and the gap value of each part in real time, so that the parallelism and the Fabry-Perot cavity length (output wavelength ) to control

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