Real-time pressure sensing method based on fiber bragg grating reflected light polarization parameter

Abstract

The invention discloses a real-time pressure sensing method based on a fiber bragg grating reflected light polarization parameter. Laser transmitted by a tunable laser (1) sequentially passes through an isolator (2), an online polarizer (3), rotational optical fiber connection ports (A and B) and a polarization controller a (4) and then enters a first port (1) and a second port (2) of a circulator (5) and is connected with a sensing fiber bragg grating (6); light reflected by the sensing fiber bragg grating (6) is output from a third port (3) and enters an online polarization detection module (8) through a polarization controller b (7) to output four paths of simulation voltage signals V1, V2, V3 and V4 containing polarization information; four paths of simulation voltage signals are converted into digital signals through an analogue / digital conversion module (9); the digital signals enter a signal processing and displaying module (10) to obtain four stokes parameters S0, S1, S2 and S3 as well as other relevant polarization parameters of reflected light in a polarization state; and the pressure borne by the sensing fiber bragg grating is sensed by monitoring and normalizing a first stokes parameter s1 being equal to S1 / S0 value in real time.

Description

technical field [0001] The invention is an optical fiber sensing device for real-time monitoring of pressure by utilizing the polarization parameter of the reflected light of the optical fiber grating. Background technique [0002] When the optical fiber is affected by the external environment (temperature, stress, magnetic field, pressure, etc.), the parameters such as the intensity, phase, frequency, and polarization state of the transmitted light in the optical fiber will change accordingly. By detecting these parameters of the transmitted light, the change of the corresponding physical quantity can be known. This technology is called fiber optic sensing technology. [0003] As a mature all-fiber device, fiber grating has very important applications in the fields of optical fiber communication and optical fiber sensing due to its small size, low insertion loss, and easy integration with other optical fiber devices. At present, most of them are Utilize wavelength shift fo...

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Problems solved by technology

In this method, when the pressure is small, it is difficult to detect the difference in the central wavelength of the two eigenmodes in the total amplitude spectrum, and it is difficult to detect

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