Optical fiber grating temperature sensor wavelength shift correction method and temperature measuring device

Abstract

The invention discloses an optical fiber grating temperature sensor wavelength shift correction method and a temperature measuring device. Correction is conducted by a wavelength shift cubic fitting method, and the fitting formula is as follows: T=K0+K1*delta(lambda)+K2*delta(lambda<2>)+K3*delta(lambda<3>), wherein T is measured temperature, delta(lambda) is wavelength shift relative to a benchmark reflection wavelength, and K0, K1, K2 and K3 are constants and need to be actually calibrated. The temperature measuring device comprises a CPU board which is connected with an OS board; the OS board is connected with multi channels of optical fibers; each channel of optical fiber is connected in series with multiple temperature measuring gratings; the OS board is further connected with an ASE board; and the ASE board is equipped with a wavelength demodulation module and a light source. The wavelength shift cubic fitting method can help to decrease the amount of calculation of temperature fitting significantly, and is easy to implement. The temperature T is calculated out directly after delta(lambda) is detected, and the real-time performance of temperature calculation is improved. By using the wavelength shift cubic fitting method put forward by the invention, the error of an optical fiber grating at 140 DEG C can be controlled within 2 DEG C.

Description

technical field [0001] The invention relates to the technical field of optical fiber grating temperature sensor correction, in particular to a method for correcting wavelength offset of an optical fiber grating temperature sensor and a temperature measuring device. Background technique [0002] The fiber grating temperature sensor has the advantages of compact structure, small size, anti-electromagnetic interference, and non-electricity. It has been widely used in high voltage, strong interference, strong corrosion, and explosion-proof occasions such as electric power, petroleum, chemical industry, coal, and fire protection. Form, precision correction and other technologies are still in constant development. The fiber grating temperature sensor is composed of grating, optical fiber, light source, detection circuit, etc., and its optical path principle is as follows: figure 1 As shown, when a beam of wide-spectrum light passes through a fiber grating, the wavelengths satisfy...

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Problems solved by technology

[0003] The quadratic fitting method is generally calibrated in the middle and low temperature area, so the quadratic fitting method has better accuracy in the middle and low temperature area, and the error is within 0.2°C, but in the middle and high temperature area (above 60°C), the error gradually increases

[0004] The existing fitting method is the quadratic or cubic fitting of the temperature T. After detecting λ, it is necessary to solve the equation to obtain T. The calculation amount is relatively large, and the implementation is relatively complicated. A single device can be used to achieve large capacity (multiple temperature measurement points) ), high real-time temperature measurement requirements, high cost, not suitable for cost-effective, large-capacity (multiple temperature measurement points) application requirements

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