Gain-transparent SOA-switch for high-bitrate OTDM add/drop multiplexing

We report on an all-optical interferometric optical time-division multiplex ing switch that exhibits high linearity, high-switching contrast, low noise , wide bandwidth, and low crosstalk, The key clement of the gain-transparen t switch is a semiconductor optical amplifier (SOA), which is transparent f or the data signal, However, the injection of optical control pulses in the gain wavelength region of the SOA leads to index modulations at the wavele ngth of the data. This variation of the refractive index can be used for in terferometric switching. In the application as add/drop multiplexer, the sw itch has the inherent advantage of leaving the nonswitched pulses undisturb ed.