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

A real-time pressure and fiber grating technology, which is applied in the measurement of the change force of the optical properties of the material when it is stressed, can solve problems such as difficult detection

Inactive Publication Date: 2014-03-19
PLA UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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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

Method used

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

Examples

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example 1

[0029] [Example 1] Design grating parameters: period Λ=535nm, fiber core refractive index n eff =1.448, length L=10mm, refractive index modulation coefficient δn=1×10 -4 . Adjust the polarization controller a4 and polarization controller b7 to perform phase compensation. Rotate the relative positions of the fiber connection ports A and B to make the polarization angle of the incident line polarized light be 45°. Selection of Tunable Laser Wavelength λ p =1549.54nm. When the sensing fiber grating 6 is affected by external pressure, the birefringence of the line will change, thus causing the first Stokes parameter of the reflected light to change. The reflected light detects the change of the polarization parameter through the linear polarization detection module 8, passes through the analog / digital conversion module 9, and displays the normalized first Stokes parameter value in real time in the signal processing and display module 10, and monitors the magnitude of the press...

example 2

[0030] [Example 2] Design grating parameters: period Λ=535nm, fiber core refractive index n eff =1.448, length L=5mm, refractive index modulation coefficient δn=0.5×10 -4. Adjust the polarization controller a4 and polarization controller b7 to perform phase compensation. Rotate the relative positions of the fiber connection ports A and B to make the polarization angle of the incident line polarized light be 45°. Selection of Tunable Laser Wavelength λ p =1549.45nm. In this example, the normalized first Stokes parameter change Δs 1 Theoretical relationship with external pressure is as image 3 As shown, the dynamic range in this example is about 15N, and the sensitivity is about 0.0667 / N.

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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...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01L1/24
Inventor 苏洋朱勇彭晖叶振兴
Owner PLA UNIV OF SCI & TECH
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