Integrated optoelectronics

Gallium-based chips supporting integrated optoelectronic circuits (IOEC) as links between electronic equipment and optical fibers are examined as viable candidates for ultrahigh speed signal switching devices. Laboratory results with GaAlAs and GaInP have shown suitable electric properties such as bulk negative resistance and high electron mobility already exploited in semiconductors. Construction of low threshold current injection lasers is described, noting the achievement of heterostructure devices which require only 8 mA/micron of stripe width. Use of a Gunn-diode oscillator on a GaAs substrate to modulate laser light in optical communications systems has been reported, as have p-i-n diode and photoconductive detectors in optoelectronic receivers. Further work with conductive substrates is outlined, and use of the IOEC devices in amplifiers, equalizers, masers, magnetic sensors, hydrophones, and gyroscopes is indicated.