In this paper, we present an integrated circuit technology suitable for low-power bias-free optical control of microwave circuits and antennas. We have integrated miniature photovoltaic arrays with varactor diodes and thin-film resistors to form monolithic optically variable capacitors (OVC's). For the monolithic OVC described here, only 1.5 mW of optical power was required for more than 2 : 1 change in capacitance (0.9-0.4 pF). Optically controlled microwave circuits such as X-band analog phase shifters and tunable notch filters, which incorporated the monolithic OVC as the control element, were fabricated to demonstrate the potential of this technology.