Device for determining temperature and deformation in an optical fiber

摘要

The arrangement uses an optical spectral analyzer to identify different Bragg wavelengths of optic fiber grating (41,42)and determines absolute physical values, temperature, from Bragg wave lengths mean wave length The arrangement uses an optical spectral analyzer, a spectrometer (6), with input pencil of light (61) arranged so that spectrally dispersed light at the dispersive element (63) is imaged onto a first line shaped receiver (64). A second pencil of light is aimed at the dispersive element (63) in the spectrometer, so that spectrally dispersed light falls on linear receiver (65) that is parallel to first receiver. There is an interferometer in the light path of the second pencil of light (62). A signal processing module (71) determines the absolute Bragg wave lengths of the optical fiber grid and hence temperature value. A phase demodulation module (72) is used to evaluate interferometer signals to determine relative changes of Bragg wavelengths of optical fiber and determine changing amounts.