Waveform shaping of chirp-controlled signal by semiconductor optical amplifier using Mach-Zehnder frequency discriminator

The optical output waveform of a semiconductor optical amplifier (SOA) is shaped using a Mach-Zehnder interferometer (MZI) as a frequency discriminator in order to suppress its distortion at high SOA input powers. This technique is applied to chirp control of an optical signal using an SOA, and the chirp control with waveform shaping greatly improves the transmission performance of a positively chirped optical signal in standard single-mode fiber over a wide range of SOA input powers. We also demonstrate that the chirp control with waveform shaping can be achieved without changing the drive settings of the SOA and MZI, even when the optical frequency is switched to another channel located on the wavelength-division-multiplexing frequency grid.