Enhanced electro-optic phase shifts in suspended waveguides.

We demonstrate enhanced electro-optic phase shifts in suspended InGaAs/InGaAsP quantum well waveguides compared to attached waveguides. The enhancement stems from an improved overlap between the optical mode and the multiple quantum well layers in thin waveguides when the semiconductor material beneath the waveguide is selectively etched. The measured voltage length product is 0.41 V-cm and the measured propagation loss is 2.3 +/- 0.7 dB/cm for the TE mode in the optical L-band.