Understanding bandwidth enhancement of all-optical turbo-switch

We propose a detailed frequency-domain model of the all-optical turbo-switch incorporating two cascaded semiconductor optical amplifiers (SOAs) with a broad band-pass optical filter in between the SOAs. The frequency-domain SOA model has taken the spatial inhomogeneity of the saturated SOA gain associated with the pump optical field into consideration for the first time. The simulations based on the model have been presented to understand the reason of the bandwidth enhancement and to predict the 3-dB bandwidth of frequency response of the turbo-switch. With the optimization of the optical powers, waveguide loss and a delayed-interferometer, the 3-dB bandwidth of turbo-switch can reach up to 270 GHz.