Quasi-Distributed Fiber-Optic Sensor With Large Measurement Range for Both Static and Dynamic Signals

Distributed fiber-optic vibration and temperature sensor are very important for many applications. However, existing multi-parameter sensing systems are usually based on a hybrid system of multiple scattering mechanisms, and thus suffer from complex system structures and high costs. Here we reported a quasi-distributed fiber-optic sensor for both static and dynamic signal measurement based on weak reflector array. A double-sideband optical frequency domain reflectometry (OFDR) is proposed to detect the beat frequency difference between adjacent weak reflectors, realizing simultaneous detection of both dynamic and static signals. The measurement range is only limited by the destructive threshold of fiber in principle. In the demonstration experiments, a temperature resolution of 0.36 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{\circ }$</tex-math></inline-formula>C and a vibration sensitivity of 30 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$p\epsilon /\sqrt{ \text{Hz} }$</tex-math></inline-formula> are achieved simultaneously with a frequency sweeping range of 6.75 GHz.