Strain based optical fiber systems

Abstract

Optical systems use tuning of in-fiber gratings to provide an optical crossbar switch matrix of switch elements. The switch elements have a drop tap and an insert tap. A combination of the switch matrices provides a flexible way of connecting any of a plurality of transmitters with any of a plurality of receivers. A distribution arrangement has a distribution station with a plurality of serially arranged modulators, each modulating a different and corresponding optical carrier supplied by optical fiber thereto. The modulated carriers are supplied by a distribution fiber to a serially arranged plurality of passive taps, each of which drops an optical carrier corresponding to the tap and supplies it to a local transceiver. The distribution arrangement may include an arrangement where a local transceiver reflects back the modulated optical carrier and modulates it with a return signal. A correlator at the distribution station detects which of several local transceivers a reflected return modulated optical carrier came from by using a time delay corresponding to the round trip transit time of the optical carrier between the distribution station and the given local transceiver. A modulation arrangement using a drop-insert tap which drops an optical carrier, modulates it, and reinserts it after providing optional amplification.