A method of manufacturing a single-fiber cascaded temperature-depth-salinity sensor for deep-sea exploration

Abstract

The invention provides a method for manufacturing a single optical fiber cascaded temperature-depth-salinity sensor for deep sea survey. The single-fiber cascaded temperature-depth-salinity sensor utilizes arc fusion and hydrogen-oxygen catalytic bonding techniques to fabricate and cascade three all-quartz sensing units on the same fiber. The introduction of multiple fiber optic miniature self-focusing lenses makes it possible to increase the sensitivity and resolution by greatly increasing the length of the two cascaded FP cavities without affecting the light transmission of the cascaded FP interferometer, so as to obtain better sensing performance. The invention not only realizes the overall all-quartz structure in the complex deep-sea detection environment, but also enables each sensing element to be cascaded on a single optical fiber, which has the advantages of small size, compact structure, high pressure resistance, corrosion resistance, and suitable for long-distance measurement. The production process is simple, repeatable, and easy to manufacture and mass-produce. It is expected to become a candidate for future deep-sea exploration and research.

Description

technical field [0001] The invention belongs to the technical field of optical fiber sensing, and relates to a method for manufacturing a single optical fiber cascaded temperature-depth-salinity sensor for deep sea surveying. Background technique [0002] Temperature, depth and salinity are important parameters required for ocean exploration and monitoring, and are of great significance to the research of oceanography, hydrometeorology, navigation and ecological balance. Currently, commercial conductance-temperature-depth (CTD) detection systems have been widely used in the study of marine environments. However, the core of the CTD system mainly relies on electronic components, which are easily affected by electromagnetic noise and seawater corrosion, and have defects such as high maintenance costs and difficult long-distance transmission. In recent years, due to the special advantages of anti-electromagnetic interference, corrosion resistance, easy distribution, networking...

AI Technical Summary

Problems solved by technology

Although this series of sensing probes has the advantages of compact structure and miniaturization, the preparation process often requires special optical fibers and complex preparation solutions, such as wet etching technology and laser micromachining, etc., which often involve making microholes inside the optical fiber, Microcavities or microchannels are not conducive to efficient mass production

Moreover, these microstructures are more susceptible to damage, making the sensor unable to be used in harsh deep-sea environments

In addition, the large transmission loss of the dual-cascade extrinsic FP interferometer without effective collimation and compensation tends to often lead to weakened signal strength and reduced fringe visibility, which affects the reading of optical signals, especially when When immersing an extrinsic open FP interferometer in a liquid for refractive index measurement

This severely limits the performance of the sensor, and even deprives the multi-parameter sensor of the underwater refractive index measurement function, resulting in the sensor being only usable in an atmospheric environment.

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