A carrier injection type optical switch in GaAs using free carrier plasma dispersion with wavelength range from 1.06 to 1.55 mu m

The switching current for the device is about 90 mA at all in-range wavelengths. Its broad wavelength range is suitable for optical signal-processing applications in wavelength-division multiplexing transmission systems. High coupling efficiency to a single-mode fiber is achieved by using a small- Delta waveguide structure with carrier blocking layers. The effective refractive index change in the waveguide per unit of the injected current density is doubled by the carrier blocking layers without reducing coupling efficiency.>