Optical-fiber low-coherence interference displacement demodulation device and method based on photoelectric oscillator

Abstract

The invention provides an optical-fiber low-coherence interference displacement demodulation device and method based on a photoelectric oscillator. A first optical fiber coupler, an adjustable light delayer and a second optical fiber coupler form a Mach-Zehnder interferometer structure, and broadband low-coherence light generates an interference light field for output through the Mach-Zehnder interferometer structure. An electrooptical modulator, an optical fiber, a photoelectric detector, a radio-frequency amplifier and a radio frequency beam splitter form the photoelectric oscillator, and the photoelectric oscillator enables the inputted interference light field to be converted into a radio signal with high spectrum purity for output. The displacement change of a position device is obtained through the measurement of the frequency value of the radio frequency signal, thereby achieving the demodulation of the low-coherence interference displacement. The method provided by the invention can be used for the high-precision detection of displacement, or for other sensors to carry out the demodulation of stress, temperature, thickness, group index of refraction and pressure into displacement.

Description

technical field [0001] The invention relates to the field of displacement information demodulation, in particular to an optical fiber low-coherence interference displacement demodulation device based on a photoelectric oscillator and a demodulation method thereof. Background technique [0002] As an important non-contact measurement method, fiber optic low-coherence interferometry technology has broad application prospects in frontier fields such as non-contact measurement of optical systems and biomedical imaging due to its advantages of simple structure, fast measurement speed and high resolution. . [0003] Fiber-optic low-coherence interferometry usually consists of a Michelson interferometer illuminated by a broadband low-coherence light source. The optical path part is connected by single-mode optical fiber, and the laser light emitted by the low-coherence light source passes through the 2x2 optical fiber coupler, and then enters the reference arm with the mirror and ...

AI Technical Summary

Problems solved by technology

The time scanning method can measure a large range, but due to the need to mechanically scan one of the mirrors, its long-term reliability and stability are poor, and the measurement accuracy is only on the order of microns

Space scanning uses linear array CCD devices for electrical scanning, which has high long-term reliability, but the pixels of linear array CCD are limited, and its measurement range is usually small, only tens of microns

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