Active optical loop-back system

Abstract

An apparatus for looping-back an optical signal in an optical communications system includes a transmitting station and a receiving station optically coupled to the transmitting station by a transmission fiber and reception fiber. Data is transmitted from the transmitting station to the receiving station through the transmission fiber and is also transmitted from the receiving station to the transmitting station through the reception fiber. The apparatus includes a beam splitter having an input port, an output port and a tap port, operationally coupled to the transmission line. The beam splitter is capable of diverting a preselected beam portion of an optical data beam being transmitted through the transmission fiber to the tap port. A tap fiber that is operationally coupled to the tap port allows the preselected beam portion to propagate therethrough. An optical analyzer, optically coupled to the tap fiber, regenerates the preselected portion, thereby creating a return beam. A return fiber, optically coupled to the optical analyzer, transmits the return beam. An optical switch, optically coupled the to reception fiber and to the return fiber, selectively optically couples the return fiber to the transmitting station through the reception fiber and selectively decouples the return fiber from the transmitting station. A switch controller, operationally coupled to the optical switch, causes the optical switch to optically couple the return fiber to the reception fiber.