High Efficiency Waveguide-Integrated 1.3 micrometers InGaAs/GaAs MSM Detector as an Optical Delay Line Switch for Microwave Phased Arrays,
Abstract
In recent years, there has been much interest in the development of waveguide-integrated detectors for applications in wavelength division multiplexing and balanced heterodyne receivers in coherent systems (l)-(3). In this paper, we report the first integration of a strained layer (In0.35GaO.65As on GaAs) metal-semiconductor-metal (MSM) detector with a GaAlAs/GaAs rib-waveguide. By optimizing the thicknesses of the epitaxial layers, we achieved an estimated coupling efficiency of 99% from the incident mode in the rib waveguide to the guided modes in the integrated-detector section. We measured a DC responsivity (lambda = 1.3 microns) as high as 0.6 mA/mW for 100-micrometer long detectors at a voltage bias of 6 V. In addition, we will present the advantages offered by this device for bias-switching waveguide delay lines designed for the optical control of microwave phased array radar. The epitaxial structure of this device (see Fig. 1 for layer thicknesses) consists of Al0.lGa0.9As and GaAs layers from which the rib waveguide was fabricated. The growth of these layers was followed by that of a thickness-graded In0.35Ga0.65As/GaAs superlattice buffer that enabled the strained In0.35Ga0.65As detection layer to be grown on the GaAs substrate. Finally, a layer (-0.02 micrometer) of InxGal-xAs (lambda -1.1 micrometer) was grown to enhance the Schottky barrier heights of metal electrodes in the MSM detector. All the epitaxial layers were grown by MOVPE in a single growth step. In fabricating the waveguide-integrated detector, we first etched a mesa from the detector layer down to the GaAs waveguiding layer.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1992
- Accession Number
- ADP008121
Entities
People
- Anoop Narayanan
- D. Yap
- R. Hayes
- Weiwen Ng
Organizations
- HRL Laboratories