Brillouin optical correlation domain reflectometry with lock-in detection scheme

We have proposed a Brillouin optical correlation domain reflectometry (BOCDR) with lock-in detection scheme. The weak and noisy spontaneous Brillouin signal is output from the electrical spectrum analyzer as an analog signal, and detected synchronously and amplified using a lock-in amplifier. By further introducing phase modulation into the system to suppress the background optical noise, and using large frequency modulation amplitude with appropriate filtering, the performance of the system is enhanced. A 4cm spatial resolution is experimented over 100m measurement range.