Temperature sensing using the spectral interference of polarization modes in a highly birefringent fiber

• The spectral interference of polarization modes in a birefringent fiber to measure temperature is analyzed.
• A tandem configuration of a birefringent delay line and a sensing fiber is considered.
• A birefringent quartz crystal of a suitable thickness is employed to resolve a channeled spectrum.
• The polarimetric sensitivity to temperature is determined in the wavelength range from 500 to 850 nm.
• Temperature sensing based on the wavelength interrogation is used.

The spectral interference of polarization modes in a highly birefringent (HB) fiber to measure temperature is analyzed theoretically and experimentally. A tandem configuration of a birefringent delay line and a sensing HB fiber is considered and the spectral interferograms are modelled for the known birefringence dispersion of the HB fiber under test. As the delay line, a birefringent quartz crystal of a suitable thickness is employed to resolve a channeled spectrum. The channeled spectra are recorded for different temperatures and the polarimetric sensitivity to temperature, determined in the spectral range from 500 to 850 nm, is decreasing with wavelength. It is demonstrated that the temperature sensing is possible using the wavelength interrogation, i.e., the position of a given interference maximum is temperature dependent. The temperature sensitivity of the HB fiber under test is −0.25 nm/K and the resolution is better than 0.5 K.