On the compensation of chirp induced from semiconductor optical amplifier on RZ data using optical delay interferometer

The capability of an optical delay interferometer (ODI) to compensate the chirp induced on return-to-zero pulses amplified by a semiconductor optical amplifier (SOA) when operated under stressful conditions for its gain dynamics is investigated and demonstrated through extensive numerical simulation. The phase response of the ODI, which through its variation per time increment determines the chirp, is calculated at its crossed output port using an explicit expression. The theoretical analysis reveals that cascading the ODI after the SOA can reduce both the magnitude of the chirp and the variations of its peaks as well as those of the amplified pulses while ensuring error-free performance even for a tight combination of the critical parameters. In order for this goal to be successfully accomplished while not distorting the pulses acted on by the ODI the offset introduced by this passive element is computationally found that it must not exceed 10% of their repetition interval. Therefore the scheme can constitute a promising technological option for efficiently exploiting the chirp of an SOA and simultaneously using the SOA as gain block for direct amplification purposes.