New temperature-sensing approach based on temperature shift of effective cutoff wavelength

A new approach for temperature sensing between 20 - 300 degree(s)C using a single mode fiber with a depressed cladding is presented. The effective cutoff wavelength (780 nm) is a linear function of temperature for this fiber because of the mismatch of the thermal expansion coefficients between the core and cladding. Consequently, the attenuation coefficient in the region of the cutoff wavelength is linearly dependent upon temperature. The advantage of this sensor is that the sensing wavelength may be selected between 600 - 780 nm.