1-cm spatial resolution with large dynamic range in strain distributed sensing by Brillouin optical correlation domain reflectometry based on intensity modulation

We experimentally demonstrate distributed strain measurement with a high spatial resolution and a large dynamic range by proposing a system for Brillouin optical correlation domain reflectometry with an intensity modulation scheme. With the optimized intensity modulation, the optical power spectrum of the light source is properly modified so that the accumulated background noise in the Brillouin gain spectrum is significantly reduced. It is confirmed that the proposed system enables us to extend the maximum measurable strain up to similar to 7000 mu epsilon, which is sufficient for practical applications of a distributed sensing, with 1-cm spatial resolution. This resolution is the best result ever reported in reflectometries based on spontaneous Brillouing scattering by using a conventional single mode fiber.