Fiber Laser Temperature and Strain Simultaneous Measurement System

Abstract

A temperature and strain simultaneous measurement system through adoption of fiber laser comprises a fiber laser, a first 980nm isolator, a second 980nm isolator, a wavelength division multiplexer, a pump light source, a first coupler and a second coupler. The fiber laser, the first 980nm isolator, the second 980nm isolator, the wavelength division multiplexer, the first coupler and the second coupler form a loop light path; a 1550nm isolator is connected with the port 3 of the first coupler; a narrow linewidth tunable laser is connected with the input end of the 1550nm isolator; a function generator is connected with the input end of the narrow linewidth tunable laser; the first detector is connected with the port 3 of the second coupler; the second detector is connected with the port 4 of the second coupler; and an oscilloscope is connected with the output ends of the first detector and the second detector. The temperature and strain simultaneous measurement system through adoption of the fiber laser can measure temperature and strain measurement resolution in the system while improving the temperature and the strain of the current fiber grating.

Description

technical field [0001] The invention relates to the technical field of simultaneous temperature and strain measurement, in particular to a fiber laser-based simultaneous temperature and strain measurement system. Background technique [0002] In the past two decades, with the continuous development of FBG manufacturing technology and demodulation technology, FBG strain and temperature sensing technologies have been widely used, especially in harsh environments such as strong electromagnetic interference, high temperature and high pressure, explosives, and chemical corrosion. shows great advantages. However, the strain (referring to static strain) and temperature cross-sensitivity of fiber gratings are the core issues that need to be solved in its practical application (Yong Zhao, Yanbiao Liao, Optics and Lasers in Engineering, vol.41, pp.1-18, 2004 ). Although in the fields of civil engineering and large-scale structural health monitoring, the conventional reference fiber ...

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Problems solved by technology

[0005] However, the existing FBG strain and temperature measurement schemes generally have strain and temperature measurement resolutions in the με and °C levels, which is still far from the requirements of high-precision strain and temperature measurement fields; Fabricating a fiber grating with a special structure to achieve simultaneous measurement of strain and temperature puts forward higher requirements for the fabrication of fiber gratings and the design of sensor probes, which is not conducive to wide application and promotion

[0006] In addition, Italian National Institute of Optics P.Malara et al. proposed a phase-shift grating strain sensor with ring optical path configuration in 2014 and 2015 (P.Malara, et al., Optics Letters, vol.39(24) , pp.6899-6902, 2014), through this optical path configuration, the reflection spectrum of the phase-shifting grating has a resonant peak frequency splitting phenomenon; and the frequency splitting distance reflects the external strain and temperature information, due to the reflection after the frequency splitting The peak line width is very narrow, and we can accurately obtain the wavelength difference information through the frequency-sweeping laser, and then obtain higher-resolution signal measurement, but this solution also cannot eliminate the temperature problem (that is, the system cannot measure temperature and strain at the same time)

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