Effect of wavelength Shift of light source in the fiber coupler evanescent wave temperature sensor system

摘要

The fiber-optic evanescent wave temperature sensor is investigated experimentally, for which the sensing probe consists of a fiber-optic coupler. The coupling visibility fluctuation of the fiber coupler probe was measured when the environmental temperature shifted center wavelength of the LD light source. From the experimental results, with the center wavelength of LD shift to longer wavelength, the transmission loss increased, and the wavelength shift of LD was about 0.5nm/°C. By using the supermode theory, the effect of wavelength shift of light source on the fiber coupler sensor was discussed.