Wavelength division multiplexing passive optical network using IM-FSK scheme

A wavelength division multiplexing passive optical network architecture with colorless user terminals based on the use of a different modulation scheme for each way of communication is proposed in this paper. Frequency-shift keying (FSK) modulation obtained by direct FSK modulation laser has been used for the downstream channel, and intensity modulation has been used for the upstream channel. The performance of a link based on this scheme has been assessed, with particular emphasis on the impact of the dispersion noise and related pre-filter choosing at OLT-side. The operation of the architecture is demonstrated by simultaneously transmitting frames at 1.25 Gb/s in both the upstream and downstream channels. Error rates for downstream and upstream channels show excellent performance for distances up to 20 km.