Photonic switching by Tunneling-assisted absorption modulation in a GaAs sawtooth.

We report on an electrically controlled optical modulator using a novel GaAs sawtooth structure. This structure consists of alternatingly n-type and p-type delta doped GaAs. Modulation of tunneling-assisted absorption is achieved by changing the internal electric field which in turn is controlled by external bias. Modulation of light-intensity is demonstrated over a broad spectral range of DELTAlambda > 100 nm. A contrast ratio of 1:1.7 of the opaque and transparent state is obtained. Low-voltage operation (DELTAV5V) and potential high-speed capability make the new device an attractive candidate for future photonic switching systems.