Coherent probe-pump-based Brillouin sensor for 100-um crack detection and 100-km distributed strain and temperature sensing

We present 100-μm crack detection and 100-km distributed strain and temperature sensing by fiber-optic distributed strain and temperature sensor (DSTS) based on coherent interaction of probe-pump. The DSTS products have been employed to detect cracks on ceramic by measuring the strain distributions along the surface of the ceramic and a continuing long-term field monitoring of local temperature and stress changes in a 70-km buried fiber-optic cable.