Optoelectronic control technology for Phased Arrays.

Phased arrays are critical for surveillance and tracking. Current TR modules use numerous MMIC chips, ferrite circulators and phase shifters and quasi-optical true-time-delay (TTD). A major power requirement is distribution and synchronization of the T/R function across multiple RF interfaces. Large scale integration could address the problem of interconnecting boards with GHZ RF outputs but is currently not possible. Such integration with optical control holds the key. OPEL proposes a monolithic IC solution based upon novel optoelectronic (OE) thryistor circuit design. Thyristor/HFET circuits implement a novel power amplifier using a gated OE oscillator driving a Class E output. The receive channel is implemented with a thyristor LNA/mixer to achieve down-conversion with gain followed by digitization with a new ƒA-ƒ' modulator. Control data/return data are coupled optically to/from a processor at a central distribution point. Clock recovery, deserialization, and optical distribution implement a low power control system. A thyristor based ripple counter implements a serializer circuit and produces the inverse TTD function for return signals. Both T and R channels are integrated using novel dielectric isolation. Optical and RF signal paths are maximized and minimized respectively to achieve a dramatic reduction in overhead power loss. OPEL will demonstrate this optoelectronic approach.