High-sensitivity seawater salt temperature two-parameter sensor based on interference vernier effect

Abstract

The invention relates to a high-sensitivity seawater salt temperature two-parameter sensor based on an interference vernier effect. The high-sensitivity seawater salt temperature two-parameter sensor is characterized by comprising a broadband light source, a 2*2 optical fiber coupler, two double-FP-cavity Fabry-Perot interferometers arranged in parallel and a spectrograph, wherein the double-FP-cavity Fabry-Perot interferometer comprises a single-mode optical fiber, an optical fiber microsphere structure with a microfluidic channel and a large-mode-field optical fiber which are arranged in sequence. According to the invention, free spectral ranges of an air cavity and a quartz cavity in the interferometer are close to each other by setting optical fiber microsphere structures with different parameters and large-mode-field optical fiber cavity lengths, a vernier effect is realized, and corresponding frequencies of output spectrums are kept at intervals; when the seawater salt temperature changes, the cavity length of the interferometer changes, Fourier transform and filtering are carried out on output spectrums, and the output spectrums and envelopes of all the interferometers are obtained; the simultaneous measurement of two parameters can be realized through the envelope signal drift distance in combination with the salinity and temperature sensitivity matrix; and the high-sensitivity seawater salt temperature two-parameter sensor has the advantages of high practicability, compact structure, high sensitivity, high stability, capability of simultaneously measuring multiple parameters and the like.

Description

technical field [0001] The invention belongs to the field of optical fiber sensing, and in particular relates to a highly sensitive seawater salt temperature dual-parameter sensor based on the interference vernier effect. The sensor has the advantages of simple structure, high sensitivity, good repeatability, and real-time and on-site accurate detection. Background technique [0002] The vernier effect uses the principle that the alignment scale of the main scale and the vernier will change in a large range when the small measurement value changes, so as to realize the enlarged reading of a small amount and improve the measurement accuracy. The vernier effect is widely used in the field of measurement. Combining the vernier effect with the fiber optic Fabry-Perot interferometer, through the cascade connection of two FP interference cavities, the superposition of the output spectral signals will form a new fringe envelope signal, and the fringe envelope can be demodulated to ...

AI Technical Summary

Problems solved by technology

[0005] Aiming at the ubiquitous problems of low sensitivity, cross-sensitivity of salinity and temperature, and poor stability of optical fiber salinity and temperature sensors, the present invention proposes a high-sensitivity seawater salt sensor based on interference vernier effect with simple structure, low cost and strong practicability. Temperature dual parameter sensor

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