Impact of dispersion, PMD, and PDL on the performance of spectrum-sliced incoherent light sources using gain-saturated semiconductor optical amplifiers

The effects of chromatic dispersion (CD), polarization-mode dispersion (PMD), and polarization-dependent loss (PDL) on the intensity noise suppression of spectrum-sliced incoherent light sources achieved by using gain-saturated (GS) semiconductor optical amplifiers (SOAs) are investigated. Passing the spectrum-sliced incoherent light through SOAs, the excess intensity noise (EIN) originating from beating of spontaneous emission against itself can be greatly reduced. However, since the noise suppression is achieved by an elaborate balancing between numerous frequency/polarization components of light, thus, forming a high correlation between them, it is vulnerable to frequency/polarization-dependent optical phenomena. Through Q-factor and bit error rate (BER) measurements, this paper shows that CD, PMD, or PDL deteriorates the SOA-based noise suppression technique by breaking the correlation. Spectral analysis is also performed to investigate the frequency dependency of these effects. It is shown that CD and PMD negate the noise suppression giving rise to intensity noise from high frequencies, whereas there is no frequency dependence for PDL effects. Therefore, CD-, PMD-, or PDL-induced penalties for incoherent light sources using the SOA-based noise suppression technique are considerably greater than those produced by pulse broadening or distortion alone.