Accession Number : ADP008121

Title :   High Efficiency Waveguide-Integrated 1.3 micrometers InGaAs/GaAs MSM Detector as an Optical Delay Line Switch for Microwave Phased Arrays,

Corporate Author : HUGHES RESEARCH LABS MALIBU CA

Personal Author(s) : NG, W. ; Narayanan, A ; Hayes, R. ; Yap, D.

Report Date : APR 1992

Pagination or Media Count : 2

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.

Descriptors :   *OPTICS, *DETECTION, *MICROWAVES, *PHASED ARRAYS, *RADAR, *SEMICONDUCTORS, *SWITCHING, *WAVEGUIDES, ARRAYS, BARRIERS, BIAS, BUFFERS, CONTROL, COHERENCE, PASSIVITY, COUPLINGS, DELAY, DELAY LINES, DETECTORS, DIELECTRICS, DIVISION, EFFICIENCY, ELECTRODES, FINGERS, GALLIUM ARSENIDES, PLATINUM, GOLD, LAYERS, METALS, MULTIPLEXING, PHOTOGRAPHS, RECEIVERS, RIBS, HETERODYNING, STRUCTURES, SUBSTRATES, SUPERLATTICES, THICKNESS, VOLTAGE, WIDTH, WINDOWS, EPITAXIAL GROWTH, ETCHING, TITANIUM.

Subject Categories : Active & Passive Radar Detection & Equipment
      Electrical and Electronic Equipment
      Radiofrequency Wave Propagation
      Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE