A dual-loop-optoelectronic-oscillator-based stimulated Brillouin scattering for temperature sensing

We propose and experimentally demonstrate a high-sensitivity and high-precision temperature sensor by interrogating a dual-loop optoelectronic oscillator (OEO) based on stimulated Brillouin scattering (SBS). In the proposed scheme, the wavelength temperature-sensitive pump light generated by the Brillouin ring laser is injected into the optical fiber in the OEO loop to complete a temperature-sensitive low-frequency SBS-based microwave photonic filter (MPF), centred at 1.17GHz. The dual-loop OEO ensures that there is only one stable oscillation mode in the MPF. A changing temperature shifts the central frequency of the MPF and that of the OEO which can be easily and accurately measured. The experimental results show that a stable single-mode oscillation with a side mode suppression ratio of up to 33dB and a high sensitivity of 1.1043MHz/℃ are achieved, where the temperature sensing error is below ±0.012℃.