Temperature measurement using a multi-wavelength fiber ring laser based on a hybrid gain medium and Sagnac interferometer.

In this paper, a multi-wavelength fiber ring laser (MWFRL) based on a hybrid gain medium and Sagnac interferometer (SI) used for temperature measurement has been proposed and experimentally demonstrated. Experiments have been carried out with polarization maintaining fibers (PMF) of different lengths, which are incorporated in the SI as sensing elements. Stable multi-wavelength oscillation at 1560 nm band is successfully achieved with the wavelength instability of ±0.08 nm and the signal-to-noise of 42 dB. The experimental results show that the wavelength change of the MWFRL with temperature variation has a good linear response and the temperature sensitivity of 1.8063 ± 0.00933 nm/°C is obtained when the length of the PMF is 1.7 m. As the length of PMF increases, the sensitivity can be improved.