Vertically Integrated A1GaAs Waveguide and GaAs Photodetector with Efficient Total-Internal-Reflection Coupling,
Abstract
We present a new approach for monolithic optical waveguide-to-photodetector coupling that enables integration of photodetectors with active integrated-optic components. Several techniques for integrating passive waveguides with photodetectors have been reported but to our knowledge integration of detectors with active waveguide modulators has not been demonstrated. This paper reports efficient monolithic coupling between low-loss AlGaAs channel waveguides and multi-GHz GaAs MSM photodetectors, using a device structure and fabrication process compatible with high-performance modulator integration. In combination with on-chip electronics, detector integration enables monolithic feedback control of analog external modulators and realization of taps for high-speed optoelectronic signal processing. A cross-sectional profile of the integrated waveguide/photodetector is shown. Optical radiation at Lambda = 0.84 um is incident from an AlGaAs single-mode strip-loaded waveguide onto an etched total-internal-reflection MR) mirror. The mirror redirects the optical beam upward through the transparent cladding, onto the backside of an overlying GaAs MSM photodetector. The AlGaAs waveguide and cladding are sufficiently thick to confine >99.9% of the guided mode within these transparent layers, ensuring low propagation loss, yet the optical path from the mirror to detector through the upper cladding is sufficiently short to prevent appreciable spreading of the unguided beam. Hence, the TIR mirror provides efficient coupling between a low-loss waveguide and small-area photodetector.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1992
- Accession Number
- ADP008092
Entities
People
- D. E. Bossi
- J. M. Berak
- R. P. Basilica
- R. W. Ade
Organizations
- United Technologies Corporation