Development and characterization of tunable laser based optical time domain reflectometer

Fiber line monitoring system is crucial in the operation of optical communication networks to minimize the system interruptions due to fiber faults. A tunable laser based optical time domain reflectometer (TL-OTDR) is developed for the purpose of detecting breakages in the fiber link. The TL-OTDR is able to inject optical pulses with different wavelengths to the fiber link and the reflected light is analyzed by the OTDR. With the integration of optical filters at the fiber ends, fiber fault at the branch can be identified by the TL-OTDR compared to the conventional OTDR which is only able to detect faults in the core fiber. An L-band tunable laser is deployed as the laser source of the OTDR without interrupting the fiber to the home (FTTH) transmission at C-band wavelengths. The TL-OTDR is characterized and the results are reported.