Implementation of Single-Sideband External Modulation for Brillouin Optical Correlation-Domain Reflectometry

Brillouin optical correlation-domain reflectometry (BOCDR) enables distributed strain and temperature measurements along optical fibers with high spatial resolution and random-access capability. Conventional BOCDR setups typically require sinusoidal laser frequency modulation, achieved either by direct or external modulation. In external modulation, double-sideband modulators (DSBMs) are generally used, but one of the sidebands must be discarded using narrowband optical filtering. Here, we propose and experimentally validate an approach that replaces the DSBM with a single-sideband modulator, eliminating the need to discard a sideband. We demonstrate efficient single-sideband modulation in BOCDR and apply the technique to measure the temperature distribution in a 100 m silica fiber.