METHOD AND APPARATUS FOR ACOUSTIC SENSING USING MULTIPLE OPTICAL PULSES

摘要

An improved technique for acoustic sensing involves, in one embodiment, launching into a medium, a plurality of groups of pulse-modulated electromagnetic-waves. The frequency of electromagnetic waves in a pulse within a group differs from the frequency of the electromagnetic waves in another pulse within the group. The energy scattered by the medium is detected and, in one embodiment, may be used to determine a characteristic of the environment of the medium. For example, if the medium is a buried optical fiber into which light pulses have been launched in accordance with the invention, the presence of acoustic waves within the region of the buried fiber can be detected.

主权项

1. A method comprising:
launching into a medium a first pair of electromagnetic waves comprising a first electromagnetic wave and a second electromagnetic wave; and sampling a first signal associated with a scattering by the medium of the first pair of electromagnetic waves by extracting phase information including complex signals corresponding to a plurality of fixed locations along the medium.