In-band optical signal-to-noise ratio monitoring technique based on Brillouin fiber ring laser.

We propose an improved technique for in-band optical signal-to-noise ratio (OSNR) monitoring based on a Brillouin fiber ring laser seeded by the optical channel to be monitored. This technique shows a reduction of the required input power into the monitor along with a large and tunable dynamic OSNR monitoring range. It is demonstrated experimentally and numerically for various bit rates and modulation formats.