Abstract

Optically controlled millimeter-wave devices such as IMPATT⁽¹⁾ and TRAPATT⁽²⁾ diode have been reported. Millimeter-wave phase shifter utilizing an electronically injected electron-hole plasma in a semiconductor waveguide has also been demonstrated.⁽³⁾ None of these devices, however, can operate at high speed. In our laboratory, we have developed a family of optoelectronic devices at the millimeter-wave spectral region which have picosecond speed capability.^(4,5) For example, the gating of millimeter-wave pulse with vasriable pulse duration ranging from a few nanoseconds to subnanoseconds has been reported. When the device is operated as a phase shifter, the phase shift as large as 1500°/cm has been observed.⁽⁵⁾ In these previous studies, we have found that, in general, the carrier diffusion will cause large loss and less phase shift for the millimeter-waves. In this work, we will report on the performance of dielectric waveguide made of silicon-on-sapphire (SOS). It is expected that the optically induced electron-hole plasma will be confined in a thin layer of epitaxially grown silicon and thus a high density but thin thickness plasma layer may be maintained, resulting in a small dynamic insertion loss.

© 1985 Optical Society of America