Direct measurement of brillouin frequency in distributed optical sensing systems

Abstract From the Canadian patent

An optical sensing system uses light scattered from a sensing fibre to sense conditions along the fibre, and has a receiver with a frequency to amplitude converter to obtain a frequency of a Brillouin component of the received scattered light, to deduce the conditions. This converter can avoid time consuming scanning of frequencies to obtain the Brillouin frequency spectrum and avoids the heavy processing load of deducing a peak or average frequency from the spectrum. The converter can be implemented in the optical domain using a grating or interferometer, or in the electrical domain using a diplexer or electrical interferometer. It can generate complementary signals having opposite …