Loss-less bridging in 1+1 optical protection using a modified transmitter and receiver

Traditional 1+1 optical layer protection is implemented by creating two signals from one via a 3-dB splitter (with ~3-dB insertion loss) and transmitting both signals along two different path-diverse optical fibers. In this letter, a transmitter has been modified to provide two signals in such a manner that no excess insertion loss is encountered. Optical protection switching using this transmitter and a modified invertible receiver is demonstrated under 10-Gb/s nonreturn-to-zero transmission. A protection time of 5 ms is obtained.