Fiber optic temperature sensor and sensing head structure

Patent metadata

Field	Value
Publication number	US-11761827-B2
Application number	US-202217910520-A
Country	US
Kind code	B2
Filing date	Mar 23, 2022
Priority date	Mar 23, 2021
Publication date	Sep 19, 2023
Grant date	Sep 19, 2023

Abstract

A fiber optic temperature sensor, a sensing head structure, and a manufacturing method are provided. The fiber optic temperature sensor includes a broad spectrum light source, a first fiber optic coupler, a spectrometer, a first sensing interferometer, and a second sensing interferometer. The first sensing interferometer and the second sensing interferometer have opposite temperature responses. A first free spectral range corresponding to the first sensing interferometer is close to but not equal to a second free spectral range corresponding to the second sensing interferometer. In the fiber optic temperature sensor, two sensing interferometers both sensitive to temperature are used, and the two sensing interferometers have opposite temperature responses, thereby achieving an enhanced vernier effect, and improving the sensitivity of temperature measurement.

First claim

What is claimed is:

1. A fiber optic temperature sensor, comprising:
a broad spectrum light source,
a first fiber optic coupler,
a spectrometer,
a first sensing interferometer, and
a second sensing interferometer;
wherein the first sensing interferometer and the second sensing interferometer have opposite temperature responses;
wherein a first free spectral range corresponding to the first sensing interferometer is not equal to a second free spectral range corresponding to the second sensing interferometer;
the first sensing interferometer is configured to be a Sagnac interferometer comprising a second fiber optic coupler and a polarizing optical fiber, and the second sensing interferometer is configured to be an F-P interferometer formed by connecting a single-mode optical fiber and a polydimethylsiloxane (PDMS) cavity; and
the fiber optic temperature sensor has a temperature sensitivity S 12 as follows:

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Assignees

• Univ Guangdong Ocean

Inventors

• Yang Yuqiang
• Mu Xiaoguang
• Wang Ji
• Liu Mingxin

Classifications

• G01K11/32 Primary

  using changes in transmittance, scattering or luminescence in optical fibres · CPC title

• G01K11/3206 Primary

  at discrete locations in the fibre, e.g. using Bragg scattering · CPC title

• G01D5/35312

  using a Fabry Perot · CPC title

• G01D5/35322

  using interferometer with one loop with several directions of circulation of the light, e.g. Sagnac interferometer · CPC title

• G01K5/58

  the solid body being constrained at more than one point, e.g. rod, plate, diaphragm (G01K5/62 takes precedence) · CPC title