Fiberguide grating sensor and manufacturing method thereof

Abstract

The present invention provides a fiberguide grating sensor, having advantages of easier demodulation, high measurement precision and stronger multiplexing capability. The fiberguide grating sensor includes an optical fiber and an optical fiber to be joined, the end face of the optical fiber is provided with a groove, the optical fiber is connected with the optical fiber to be joined through buttjunction, the groove is formed to a cavity, the optical fiber to be joined is formed to a waveguide diaphragm, and the waveguide diaphragm is processed with a plurality of periodicity microflutes. By preparing a periodic waveguide grating structure on the waveguide diaphragm, it is capable of forming a waveguide grating for reflecting a specific wavelength, the bandwidth of the reflected wavelengthis narrow, and it is capable of obtaining the better measurement precision and the multiplexing capability; comparing with the common optical fiber grating, the waveguide grating with a cavity structure has a high sensitivity, and is capable of sensing the outside temperature, pressure and refractive index variation directly; by employing a whole optical fiber structure, the invention has a stronghigh temperature resistance capability, and it is capable of changing the range of the sensor by changing the dimension of the optical fiber and the diameter of the cavity.

Description

technical field [0001] The invention belongs to the technical field of optical fiber sensing, and in particular relates to an optical fiber waveguide grating sensor which can be used to measure temperature, refractive index and pressure and a manufacturing method thereof. technical background [0002] In the large family of sensors, fiber optic sensors have a series of advantages such as intrinsically safe, free from electromagnetic interference, convenient for networking and long-distance telemetry, and suitable for harsh environments, and have gradually become one of the mainstream development directions of the new generation of sensor technology. [0003] In fiber optic sensors, the sensors used for temperature, strain and pressure measurement are mainly fiber Bragg gratings (FBG) and Fabry interferometers. The application has been greatly restricted, but its small cross-sensitivity is very suitable for temperature, strain and pressure measurement. However, the current op...

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Problems solved by technology

[0003] In fiber optic sensors, the sensors used for temperature, strain and pressure measurement are mainly fiber Bragg gratings (FBG) and Fabry interferometers. The application has been greatly restricted, but its small cross-sensitivity is very suitable for temperature, strain and pressure measurement. However, the current optical fiber sensor uses a catheter to connect two sections of optical fiber, which has poor mechanical stability and is not durable. High temperature, its production mainly relies on manual production and packaging, and its yield and product repetition rate cannot be guaranteed

[0004] JP2001280922 and WO2005121697 disclose a F-P sensor. Due to the corrosion process, it is only suitable for multi-mode optical fibers. The sensor cavity must be a multi-mode optical fiber, and the production efficiency is low. It is difficult to make a pressure sensor by cutting the optical fiber; one optical reflective surface of the FAP sensor is a corroded curved concave surface, and its reflection performance is not good, resulting in poor optical performance of the FAP sensor and low contrast of the sensor reflection stripes (<10dB), so that the measurement accuracy is limited; one end of the sensor is a multi-mode fiber, the sensor has a large insertion loss, poor optical performance, and the connection loss with the existing ordinary single-mode fiber is large

The interference fringes of the Fappa cavity are wide, the multiplexing ability is not strong, and the signal demodulation is complicated

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