Interchannel interference effects in spectrum-sliced WDM systems

In spectrum-sliced WDM systems with an optical preamplifier receiver there is an optimum m = B0T (B0 = optical channel bandwidth, T = bit duration) to minimize the average number of photons-per-bit (N,,) required at the receiver for a given error probability (Pe). These results, previously obtained for the case of rectangular filters and no interchannel interference, are extended to the case of practical filters. It is shown that interchannel interference increases the optimum m and the minimum N,. Operating at this optimum, the total system throughput with first-order filters is maximized at a channel spacing-to-bandwidth ratio of 3.3, and this throughput is 3 1 Gbits/s when the total system bandwidth is 4.4 THz (35 nm). Key words: wavelength-division multiplexing, spectrum slicing, interchannel interference, optical amplifier receiver