Brillouin optical time-domain reflectometer based on a silicon photonic integrated transceiver

We present a Brillouin optical time-domain reflectometer (BOTDR) using a silicon photonic integrated transmitter-receiver. This integrated transceiver comprises a Mach-Zehnder modulator (MZM) for transmitting, a dual-quadrature and dual-polarization balanced photodetection unit for coherent receiving, and auxiliary optics including a polarization controller (PC) and an adjustable beam splitter (BS). The integrated transceiver, combined with a discrete light source, an optical amplifier, a filter, a circulator, and electronic devices, forms a BOTDR interrogator. In a classical pulse train test under the configuration of 10 km single-mode fiber, 5 m spatial resolution (SR), and 550 times of averaging, the system performance achieves a Brillouin frequency shift (BFS) resolution of 0.74 MHz, which is comparable to that of the BOTDR with discrete devices. To the best of our knowledge, this is the first demonstration of a BOTDR using a dedicated integrated transceiver.