Fiber bragg grating temperature detection method by utilizing characteristic of polarization-dependent loss
A polarization dependent loss, fiber grating technology, applied in the direction of thermometers, thermometers, measuring devices, etc. with physical/chemical changes, can solve the problem that it is difficult to accurately determine the center wavelength of reflected light and so on
Inactive Publication Date: 2013-03-13
HARBIN NORMAL UNIVERSITY
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[0004] The purpose of the present invention is to provide a fiber grating temperature detection method using polarization-dependent loss characteristics to solve the problem that when using the reflected light wavelength change to measure the temperature change to be measured, it is difficult to accurately determine the central wavelength of the reflected light because the reflected light wavelength is a range value question
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[0013] Specific implementation mode one: combine Figure 1 to Figure 4 This embodiment will be specifically described. The method of this embodiment includes the following steps: 1. Reflecting the incident light after entering the fiber grating, the fiber grating is a polarization-dependent grating; the incident light is a broadband flat light source covering the maximum moving range of the fiber grating reflection spectrum. 2. The obtained reflected light has a spectral difference in the direction of the long axis and short axis selected by the polarization grating. The PDL analysis and demodulator installed in the reflection light path of the fiber Bragg grating uses the spectral difference to obtain the polarization-dependent loss value of the fiber Bragg grating. Influenced by the change of the measured temperature, the reflection peak moves, and at the same time causes the change of the polarization-dependent loss peak value; 3. The change of the polarization-dependent lo...
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The invention discloses a fiber bragg grating temperature detection method by utilizing characteristic of polarization-dependent loss, relating to a method for detecting change of temperature by fiber bragg grating. The invention is used for detecting the change of temperature. According to the method, the problem that when the change of temperature is measured by using the change of reflected light wavelength, the reflected light wavelength change value is difficult to be accurately determined due to that the reflective light wavelength is a range value is solved. The method provided by the invention comprises the steps of: first, reflecting the reflective light after being incident to the fiber bragg grating, wherein the fiber bragg grating is polarization-dependent grating; second, obtaining fiber bragg grating polarization-dependent loss values by a PDL analysis demodulation device arranged on the reflective light path of the fiber bragg grating according to spectrum difference, wherein the spectrum difference of the reflective light appears in long and short axis directions selected by the polarization grating; and third, converting the change of the fiber bragg grating polarization-dependent loss values obtained by the PDL analysis demodulation device into the value of change of external environment temperature.
Description
technical field [0001] The invention relates to a method for detecting temperature changes using an optical fiber grating. Background technique [0002] Fiber Bragg grating sensing technology is a relatively mature sensing technology at present. Fiber Bragg grating uses the photosensitivity of optical fiber materials to write the coherent field pattern of incident light into the fiber core through ultraviolet light exposure, and generates in the fiber core along the fiber core axis. The refractive index of the direction changes periodically to form a permanent spatial phase grating. The essence is to form a narrow-band (transmission or reflection) filter or mirror in the fiber core. Using this feature, many optical fiber devices with unique performance can be manufactured. They all have a large adjustable range of reflection peak wavelength, small additional loss, small size, easy to couple with optical fiber, compatible with other optical devices, and are not subject to env...
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IPC IPC(8): G01K11/32G01K11/3206
Inventor 励强华张剑田春华高社成
Owner HARBIN NORMAL UNIVERSITY