An SBS-Based Optoelectronic Oscillator for High-Speed and High-Sensitivity Temperature Sensing

We propose and experimentally demonstrate a high-speed and high-sensitivity temperature sensor by interrogating a low-frequency optoelectronic oscillator (OEO) based on stimulated Brillouin scattering (SBS). In the proposed scheme, two types of optical fibers are employed to achieve self-induced SBS and SBS-based microwave photonic filtering outside and inside the OEO cavity, respectively. Through using the fiber outside the OEO cavity as the sensing element, a temperature-sensitive low-frequency microwave signal with its frequency equal to the Brillouin frequency shift difference of the two fibers oscillates in the OEO, which facilitates high-speed and high-resolution interrogation by using digital detection and fast Fourier transform calculation. In the proof-of-concept experiment, a high sensitivity of 1.364 MHz/°C is realized by interrogating signals around 1.2 GHz, where the temperature sensing error is below ±0.3 °C.