Stimulated Brillouin scattering slow-light-based fiber-optic temperature sensor.

We propose and experimentally demonstrate a method for temperature sensing using stimulated Brillouin scattering (SBS)-based slow light. The approach relies on temperature dependence of the Brillouin frequency shift in a fiber, hence the time delay of an input probe pulse. By measuring the delay, temperature sensing can be realized. We achieve temperature measurement in a 100 m single-mode fiber (SMF) using a cw pump. The main temperature-sensing range is ∼18°C from the room temperature, limited by the SBS gain bandwidth. To apply the technique for measurement of a shorter fiber segment, a pulsed pump is used to introduce SBS slow light. Temperature sensing is achieved in a 2 m SMF with a main sensing range of around ∼25°C. The scheme is easily implemented, exhibits a relatively high temperature sensitivity with a resolution better than 1.0°C, and is potentially applicable for distributed sensing.