Abstract: A hybrid lidar-radar system for detecting the presence of objects, such as cancerous tumors, within tissues by detecting reflected signals from the tissue and discriminating the information related to the cancerous tumor from the undesirable backscattering of light created by the tissue itself. The hybrid lidar-radar system utilizes continuous wave light that is preferably modulated at frequencies up to 60 GHz. The present invention filters the return signals from the tissue at a subcarrier modulation frequency so as to reject erroneous information contained in scattered lights, while at the same time retaining the coherent, unscattered and modulated light information so as to provide for an accuracy detection of tumors within tissues.

Abstract: A hybrid lidar-radar system for detecting the presence of objects, such as cancerous tumors, within tissues by detecting reflected signals from the tissue and discriminating the information related to the cancerous tumor from the undesirable backscattering of light created by the tissue itself. The hybrid lidar-radar system utilizes continuous wave light that is preferably modulated at frequencies up to 60 GHz. The present invention filters the return signals from the tissue at a subcarrier modulation frequency so as to reject erroneous information contained in scattered lights, while at the same time retaining the coherent, unscattered and modulated light information so as to provide for an accuracy detection of tumors within tissues.

Abstract: A modulated LIDAR system is disclosed, in which a laser for generating an tical carrier signal and a microwave generator for generating a coded microwave signal are provided. A modulator is further provided for modulating the carrier signal with the microwave signal, whereby a modulated signal is generated. A method of detecting a reflective surface is also disclosed, in which an optical carrier signal is generated, the carrier signal is modulated with a coded microwave signal, the modulated signal is reflected off of a reflective surface and the reflected signal is recovered.

Abstract: An optically coupled FET comprised of bottom layer, a top layer in which FET is formed and an intermediate layer having a waveguide communicating with a grating in registration with the FET.

Abstract: An optical detector comprised of a MESFET having a larger than usual separation between its source and drain electrodes and a channel between the source and drain electrodes doped with carriers having a density of at least 10.sup.18 /cm.sup.3 whereby variation in the voltage of the gate electrode changes the optical gain.

Abstract: An integrated optical intensity modulator. The modulator is an optical waveguide on a semi-insulating substrate and having a core layer for transmitting an optical signal. The modulator includes contiguous the core layer an active cladding which has a multicoupled quantum well structure. The multicoupled quantum well includes at least one pair of quantum wells separated by a barrier. The modulator further includes first and second additional claddings wherein the core layer and the active cladding are interposed between the additional claddings. A voltage source generates an electric field through the active cladding which varies the refractive index of the active cladding as a function of the strength of the electric field for modulating the optical signal.

Abstract: An optically controlled active impedance element particularly suited to se as a tuneable inductive element for a microwave oscillator is disclosed. The optically controlled active inductive element is comprised of a circuit arrangement, preferably consisting of MESFET devices which exhibit a composite inductive characteristics, and whose inductance may be determined and controlled by direct illumination impinging on the MESFETs. The optically controlled active inductive element lends itself to being adapted to monolithic microwave integrated circuit (MMIC) applications and may find use in a wide variety of microwave circuits. Also disclosed, is an embodiment which uses the optical controlled active impedance element, in a prescribed manner, to serve as a tuneable capacitor for use in various microwave circuits.

Abstract: An optically controlled active impedance element particularly suited to se as a tuneable inductive element for a microwave oscillator is disclosed. The optically controlled active inductive element is comprised of a circuit arrangement, preferably consisting of MESFET devices which exhibit a composite inductive characteristics, and whose inductance may be determined and controlled by direct illumination impinging on the MESFETs. The optically controlled active inductive element lends itself to being adapted to monolithic microwave integrated circuit (MMIC) applications and may find use in a wide variety of microwave circuits. Also disclosed, is an embodiment which used the optical controlled active impedance element, in a prescribed manner, to serve as a tuneable capacitor for use in various microwave circuits.

Abstract: A method and system for steering an antenna beam are provided. A light source emits light wherein at least one parameter of the emitted light is modulated. Modulated light is received by an optical detector and an analog control signal is provided by the optical detector in response to the modulated parameter. The control signal is applied to an analog-to-digital converter to convert the signal from analog to digital. The digital converter output signal is applied to a digital phase shifter for controlling the phase shift of the phase shifter and thereby steering an antenna beam according to the modulated parameter. The modulated parameter may be, for example, the intensity of the emitted light or the frequency of the emitted light. A plurality of converters and phase shifters may be provided for steering of phased array antennas.

Abstract: An optical gain control circuit for controlling the gain of a GaAs MMIC dributed amplifier having a dc gain control is provided. Variable intensity light from a controlled LED is directed to the surface of a GaAs multi-finger FET by means of an optical fiber. The FET is gate biased to a point near pinch-off to maximize its light sensitivity and the drain and source of the FET are serially connected with a fixed resistance in a dc voltage divider circuit so that the output of the voltage divider circuit changes as a function of the change in light intensity of the LED. A MMIC operational amplifier connected in an inverter mode is coupled between the output of the voltage divider circuit and the dc gain control of the distributed amplifier to control the gain of that amplifier.

Abstract: An optically controlled phased array antenna system and method of operating same utilizing fiber optic transmission lengths and controlled piezo-electric crystals or equivalent elements to introduce predetermined time delays into each light signal by controlling the respective length of each fiber optic link. The light carrying fibers are wrapped around the respective crystals in accordance with a pattern to introduce time delays corresponding to the amount of stretch given to the fiber by the energized crystals. Beam scanning is achieved by controlling the matrix of crystals to introduce appropriate time delays into the optical signals which drive the respective antenna elements.

Abstract: The characteristics of antennas are modified by photosensitive electrical elements connected to the radiating elements. The photosensitive elements are biased by light, by direct electrical bias, or both. The photosensitive element may be a PIN diode. The bias may be applied by general illumination or conducted by a fiber optic cable.

Abstract: A TEM-mode transmission line such as a microstrip or coplanar line includes a pair of conductors, at least one of which is elongated. A semiconductor junction or junctions are coupled across the conductors. If a single junction is used, the junction may be laterally elongated or distributed. If discrete semiconductor junction devices are used, plural devices may be coupled across the transmission line. The capacitance of the junction(s) controls the phase shift imparted by the transmission lines to AC signals traversing the line. The capacitance of the semiconductor junctions in controlled by light coupled into the junction region. The light is coupled to the junction region by fiber-optic cables or by means of light illuminating the junction.