GaAs / AlGaAs SQW Optical Switch on Si

Abstract

ABSTRACTWe reported a waveguide-type optical switch fabricated on a Si substrate which utilized the Quantum Confined Stark Effect (QCSE). The prepared sample is an Al0.3Ga0.7As (cladding layer) / Al0.25Ga0.75As (guiding layer) double-heterostructure (DH) optical switch with a GaAs single quantum well (SQW) in the guiding layer by MOCVD. The absorption edge of the sample is measured by photocurrent method under reverse bias using a cw Ti: Sapphire laser for a light source. We measured about 10 nm shift of the absorption edge at -8 V from the sample with 8.3 nm SQW. This result demonstrates the Stark-shift effect of GaAs SQW on Si. A 2.5 μm-width ridge was formed by etching in the top cladding layer and the light traveling in the guiding layer was confined to a fundamental mode in vertical (parallel to growth direction) and horizontal direction. This switch showed 33.1 dB/mm modulation at 867 nm wavelength in -8 V bias.