Wavelength-Time Coding for Ultra Dense Wavelength Multiplexing

By reducing channel spacing in dense wavelength division multiplexing (U-DWDM), the total bitrate can be significantly increased. To cope with the resulting strong interchannel interference (ICI), a novel coding scheme is presented, which encodes and decodes in both time and wavelength direction (wavelength-time coding, WTC). The scheme is described in quite some detail. Performance is compared to conventional U-DWDM with strict optical filtering to prevent ICI, however to the expense of increased intersymbol interference (ISI).