Optical coupling of GaAs photodetectors integrated with lithium niobate waveguides

• Published in: IEEE photonics technology letters Vol. 2; no. 3; pp. 194 - 196
• Main Authors: Chan, W.K., Yi-Yan, A., Gmitter, T.J., Florez, L.T., Jackel, J.L., Hwang, D.M., Yablonovitch, E., Bhat, R., Harbison, J.P.
• Format: Journal Article
• Language: English
• Published: United States IEEE 01.03.1990
• Subjects: 360204 > Ceramics, Cermets, & Refractories > Physical Properties; 360603 > Materials > Properties; 426000 > Engineering > Components, Electron Devices & Circuits > (1990-); Absorption; ARSENIC COMPOUNDS; ARSENIDES; COUPLING; Detectors; ELECTRONIC CIRCUITS; ENGINEERING; Gallium arsenide; GALLIUM ARSENIDES; GALLIUM COMPOUNDS; INTEGRATED CIRCUITS; Integrated optics; INTERFACES; Lithium niobate; MATERIALS SCIENCE; MICROELECTRONIC CIRCUITS; NIOBATES; NIOBIUM COMPOUNDS; Optical coupling; OPTICAL PROPERTIES; Optical waveguides; OTHER INSTRUMENTATION; OXYGEN COMPOUNDS; PHOTODETECTORS; PHYSICAL PROPERTIES; PNICTIDES; REFRACTORY METAL COMPOUNDS; SEMICONDUCTOR DEVICES; SEMICONDUCTOR DIODES; Semiconductor materials; Semiconductor waveguides; TRANSITION ELEMENT COMPOUNDS 440600 > Optical Instrumentation > (1990-); WAVEGUIDES
• ISSN: 1041-1135; 1941-0174
• DOI: 10.1109/68.50887

The optical coupling of GaAs photodetectors integrated with LiNbO/sub 3/ waveguides using epitaxial liftoff is measured and compared to calculations based on a complex index model. The measured coupling is found to be comparable to that obtained in epitaxial semiconductor waveguide detectors, but it is lower than expected. Low coupling efficiency is attributed to the presence of a low index barrier layer, not present in semiconductor-based structures, at the GaAs-LiNbO/sub 3/ interface. A simple method of restoring the coupling to its original value without the need to eliminate the barrier layer is proposed.< >