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NASA NTRS1989

Computer Aided Design of Computer Generated Holograms for electron beam fabrication

Computer Aided Design (CAD) systems that have been developed for electrical and mechanical design tasks are also effective tools for the process of designing Computer Generated Holograms (CGHs), particularly when these holograms are to be fabricated using electron beam lithography. CAD workstations provide efficient and convenient means of computing, storing, displaying, and preparing for fabrication many of the features that are common to CGH designs. Experience gained in the process of designing CGHs with various types of encoding methods is presented. Suggestions are made so that future workstations may further accommodate the CGH design process.

Urquhart, Kristopher S.↗

NASA NTRS1987

Implementation of optical interconnections for VLSI

This paper reports on the progress in implementing optical interconnections for VLSI. Four areas are covered: (1) the holographic optical element (HOE), (2) the laser sources, (3) the detectors and associated circuits forming an optically addressed gate, and (4) interconnection experiments in which five gates are actuated from one source. A laser scanner system with a resolution of 12 x 20 microns has been utilized to generate the HOEs. Diffraction efficiency of the HOE and diffracted spot size have been measured. Stock lasers have been modified with a high-frequency package for interconnect experiments, and buried heterostructure fabrication techniques have been pursued. Measurements have been made on the fabricated photodetectors to determine dark current, responsivity, and response time. The optical gates and the overall chip have been driven successfully with an input light beam, as well as with the optical signal interconnected through the one to five holograms.

Wu, Wennie H.↗