Chirp characterization of SOAs under sub-nanosecond electro-optical switching using heterodyne signal post-processing

A technique to characterize amplitude distortions and optical carrier frequency variations (chirp) using optical heterodyne reception and data post-processing is presented. Predominantly, dynamic performances of electrooptical switching action based on semiconductor optical amplifiers (SOA) are analyzed, through the measuring of the SOA chirp imposed on the switched optical carrier. The employment of nearly linear SOAs is preferable in comparison with its nonlinear counterparts since the slower operational state transitions are compensated by narrower guard times and less drastic transient behaviors. At its best operational condition, the most linear SOA achieved chirp oscillations below 0.4 GHz. Its short transient behavior indicates the possibility to achieve optical package switching with low latency and low amplitude and frequency distortions. (AU)