On Optically Modulated Reflective Semiconductor Optical Amplifier Pattern-Dependent Overshoot Mitigation Using a Birefringent Fiber Loop

Reflective semiconductor optical amplifiers (RSOAs) are key elements for modern optical communications. Despite their widespread deployment, their performance when intended for ultrafast data amplification is limited by their inherently slow gain dynamics. In this paper, we propose to employ a birefringent fiber loop (BFL) to compensate for the RSOA pattern-dependent behavior and extend its operation well beyond that allowed by its nominal optical modulation bandwidth. We apply a reduced model to describe the RSOA response and quantify the RSOA output distortion by means of a non-return-to-zero data pulse overshoot. We validate the outcomes of this model in the time domain both for the RSOA alone and with the assistance of the BFL by an extensive comparison to available measurements. The excellent matching between simulation and experimental results allows us to further investigate the impact of critical operating parameters and derive specifications for them so that the performance of the scheme against the overshoot is made acceptable. The theoretical predictions confirm the ability of the BFL to enhance the RSOA direct amplification capability and hence establish it as a frequency discriminator for complementing RSOAs' versatile and scalable operation.