Metal-semiconductor waveguides for application to optical-optical switching

A novel semiconductor all-optical switching technique is presented for application to ultrashort infrared laser pulse switching. An air-filled metal-clad semiconductor waveguide is illuminated with femtosecond above bandgap laser radiation. Guided wave electromagnetic analysis-combined with time-varying dielectric properties of the semiconductor layer-is used to investigate the ultrafast switching speed of the structure. The device is capable of modulation at various infrared wavelengths. We investigate modulation of the quasi TE/sub 10/ mode of 10.6 /spl mu/m laser radiation for an electron-hole (e-h) photoinjection density of /spl sim/1.8/spl times/10/sup 18/ cm/sup -3/. The resulting extinction ratio of 83 dB is significantly higher than that exhibited by current optical-optical semiconductor switches.