Performance Improvement of Ultranarrow Spectrum Sliced Incoherent Light Using Offset Filtering

We report on the improved bit-error-rate (BER) performance of 12.5-Gb/s ultranarrow spectrum-sliced incoherent light signals by using offset optical filtering. We show that a gain-saturated semiconductor optical amplifier creates a correlation between amplitude and frequency (or chirp) of the incoherent light signals. Offset optical filtering then converts the chirp into amplitude to produce destructive interference with the excess intensity noise inherent in the spectrum-sliced incoherent light signals. The simple offset filtering lowers an error floor by a factor of two near forward-error correction (FEC) threshold, which will greatly improve the corrected BER after FEC decoding.