iDFC™ Series SFP Transceivers transmit and receive full duplex data over conventional two-fiber optical communication links. Upon disruption of the data link, or failure to connect, the Transmitter Section of the SFP unit switches into TxOTDR™ Mode. Fiber faults and intermittent connections present optical reflections of varying intensities. The reflection intensity of a fiber break has a known statistical distribution. Monitoring multiple fibers in the same trunk increases the detection probability (each fiber breaks differently). Fiber link may be monitored from one side, or both sides, when ring topology is utilized.
The new ORL/OSNR Measurement feature of the Micro-OTDR SFPs measures the optical fiber link ORL during the normal Micro-OTDR start-up “handshaking” routine of the SFPs, before the data link is made. The receiver also measures the signal received. Internally the Micro-OTDR SFP calculates the actual SNR. If the SNR is deemed to be dangerously low a Warning bit is activated, and when it is too low (i.e. the optical data link bit error rate will be high), an Alarm bit is set and optionally (factory setting based on customer request) the link can be shut-down.
