Abstract

Y-branch electro-optic waveguide switches based on modal evolution ¹ (rather than modal interference) have received wide attention for their wavelength- and polarization-insensitive properties. Semiconductor Y-branch switches^{2 3} usually employ current injection since large refractive index changes are required . Compared to current injection, electrooptic switches possess the advantages of high speed and low power dissipation. However, most voltage-controlled y-branches suffer high drive voltage requirements due to weak electrooptic effects. Recently a waveguide structure has been demonstrated that produces large electrooptic phase shifts with high-speed ( > 10 Gbps) capability⁴. Interferometric waveguide modulators⁵ based on the InGaAs /InAlAs/InGaAlAs Barrier, Reservoir, and Quantum Well Electron Transfer Structure (BRAQWETS) have employed 70 Â InGaAs quantum wells for electrorefraction at 1.58 µm.

© 1993 Optical Society of America