Parallel FEC code in high-speed optical transmission systems

Parallel FEC code transmission is proposed, in which check bits are transmitted on a different wavelength. The signal format is perfectly compatible with SDH in terms of signal wavelength. A smooth upgrade to the FEC system is possible by connecting additional modules. High FEC capability is obtained such that the BER of 10^-6 can be improved to 10^-11 with a decoding delay of several bits. When the parallel processing number is 8, the GVD tolerance is extended by a factor of 2.5, while the number of L-REPs possible in an optical link is doubled