Common-path double-wavelength orthogonal phase demodulating system

Abstract

The invention belongs to the technical field of optical fiber sensing and discloses a common-path double-wavelength orthogonal phase demodulating system. The system comprises a core control board, a fast widely-tunable laser, an optical fiber circulator, a double-beam interference type optical fiber sensor, a photoelectric detector and a computer. The core control board realizes output wavelengthdriving of the laser and synchronous acquisition and transmission of data of the photoelectric detector. The widely-tunable laser can achieve thenanosecond-order wavelength switching speed; two orthogonal wavelengths are sequentially output; and two orthogonal signals for phase signal extraction are generated. The common-path double-wavelength orthogonal phase demodulating system can solve the following three main problems of an existing double-wavelength phase demodulating system, the problems includepower imbalance and crosstalk caused by double optical paths, restrictions between the doublewavelengths and the cavity length, and elimination of a direct-current component of an interference fringe. The common-path double-wavelength orthogonal phase demodulating system realizes high-speedphase demodulation of any cavity length in an optical path through fast wavelength switching, and can be widely applied to the fields of high-speed vibration sensing, acoustic sensing and the like.

Description

technical field

[0001] The invention belongs to the technical field of optical fiber sensing, and uses a fast and wide tunable laser to realize dual-wavelength quadrature phase demodulation in one optical path. Background technique

[0002] High-performance dynamic sensing of acoustic or vibration signals has found widespread applications, such as nondestructive testing, process control, and structural condition monitoring. Fiber optic sensor is a high-speed dynamic sensor technology with great potential due to its compact structure, high sensitivity, anti-electromagnetic interference, remote monitoring, and multiplexing capabilities. Interferometric fiber optic sensors are usually based on four basic structures: fiber Mach-Zehnder interferometer, fiber Michelson interferometer, fiber Sagnac interferometer and fiber Fabry-Perot interferometer. Among them, the extrinsic Fabry-Perot interference sensing sensor (EFPI) has been widely used due to its advantages of simple struct...

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