Abstract: Lossless guided-wave switches with more than 30 dB of crosstalk-isolation are comprised of branched channel waveguides with laser-like cross-sections. Optical gain, sufficient to overcome power-splitting losses, is provided by carrier-injection currents. Due to its low-noise properties, the single-quantum-well structure is found to be optimum for cascading switches into a multi-stage network. A lossless 1.times.N network with 1024 switched outputs should be feasible.

Abstract: In multiple quantum well directional couplers, non-centralized input and output legs, occupying major portions of the switches, are continuously forward biased, to produce sufficient gain in light intensity therein to overcome losses in the centralized portions, to in turn provide a transparent (ODB loss) two-by-two coupler switch. Short segments of the centralized coupling portion occupying minor portions of the switches, are switched between forward bias states and zero bias states to provide light beam switching. Thus these switches employ both carrier gain and carrier refraction. The large changes in the index of refraction enable extremely short, low loss, switches to be fabricated and cascaded if desired. A second group of less preferred switches employ solely the carrier refraction effect, by injecting carriers into the waveguides at high levels, preferably equal to or greater than 1.times.10.sup.18 /cm.sup.3.

Abstract: This invention comprises a new group of fiber optic switching devices that use layers of surface-established ferroelectric liquid crystals (FLCs) as the switching media. In each of the devices light impinges upon the ferroelectric liquid crystal at an angle of 90.degree. (normal incidence) with the surface plane. Each FLC gives 0.degree. or .pi..degree. optical rotation, depending upon the polarity of the electric voltage applied. A series of polarizing beam splitters are used to separate unpolarized light into its s and p polarization components. After ferroelectric liquid crystal switching, other polarizing beam splitters are used to direct the s and p light to output optical paths. The switches discussed below are voltage controlled 2.times.2, 1.times.4, 1.times.6, 1.times.8, 4.times.4, or N.times.N devices that use one or more layers of surface stabilized ferroelectric liquid crystals.

Abstract: A double-injection transistor structure with an MOS gate is utilized as a guided-wave electro-optic phase modulator at infrared wavelengths in a silicon-on-insulator (SOI) waveguide. Cathode, gate and anode regions are integrated in the waveguide, longitudinally. The effective phase modulation is given by the voltage-variable overlap of the guided-mode optical field with carrier-induced local changes in the silicon refractive index. An electron-hole plasma is injected under the gate by cathode and anode. Using depletion-layer widening, the plasma channel width and mode overlap are controlled very rapidly by one or two low-power gate electrodes.

Abstract: This invention comprises a new group of fiber optic switching devices that use layers of surface-established ferroelectric liquid crystals (FLCs) as the switching media. In each of the devices light impinges upon the ferroelectric liquid crystal a an angle of 90 degrees (normal incidence) with the surface plane. Each FLC gives 0 degrees or 90 degree optical rotation, depending upon the polarity of the electric voltage applied. A series of polarizing beam splitters are used to separate unpolarized light into its s and P polarization components. After ferroelectric liquid crystal switching, other polarizing beam splitters are used to direct the s and p light to output optical paths. The switches discussed include voltage controlled 2.times.2, 1.times.4, 1.times.6, 1.times.8, 4.times.4 and dual plane devices that use one or more layers of surface stabilized ferroelectric liquid crystals to direct optical signals.

Abstract: The present invention provides improved optical switching and modulation through the use of electrically assisted opto-optical devices and optically assisted electro-optical devices. The modulator and switches 34, 60 are guided wave devices comprising silicon channel waveguides on a sapphire substrate. An optically transparent sapphire substrate 12, 42, 62 is used to allow transmission of short wavelength light through the substrate to operate upon the silicon channels in the area of p-n junctions. This permits the construction of dual control electro-optical devices. These guided wave devices operate on light at wavelengths of 1.3 microns or higher.

Abstract: The invention comprises integral all silicon light sources and 3-D optical waveguides which combine the functions of room temperature optical emission and optical signal routing. Several light emitting electrooptical silicon devices are herein disclosed. Light emitted by silicon LEDs is concentrated in channels (waveguides) and is directed to desired locations on a silicon wafer. In all of the devices, the light source is electrically actuated by a forward biased p-n junction and the light intensity can be electrically controlled by varying the applied current.

Abstract: This invention describes an infrared lightwave modulation and switching aratus for very rapidly changing the refractive index of a light-transmitting, doped, semiconductor waveguide. Electrical control is exerted by a MIS diode or MISFET. The apparatus includes a transparent crystalline silicon waveguide, an electrically insulating dielectric layer overlaying a portion of that waveguide, and an elongated, conductive gate electrode in contact with the insulator. A gate voltage applied between the semiconductor and gate serves to deplete free charge carriers from the region of the waveguide under the gate. Elongated source and drain electrodes may be added to enhance electro-optic control.

Abstract: The invention comprises a Schottky barrier type infrared photodetector which is monolithically integrated on a silicon waveguide. A Schottky barrier contact is positioned directly on a silicon waveguide to absorb grazing incidence optical signals passing through the waveguide. The Schottky contact is operated in the avalanche or reverse bias mode to generate a useable electrical signal.

Abstract: A method of fabricating low loss silicon optical waveguides by high energy ion implantation which converts a buried region into dielectric material. The top silicon surface can them be etched or formed into waveguides that are isolated by the buried dielectric. Annealing of the top silicon layer can be used to improve optical quality and additional silicon can be added to the top surface waveguides by epitaxial growth.

Abstract: All silicon electrooptic devices for modulating and switching of guided light have been developed using the silicon-on-insulator approach. Generally, p-n junctions are formed in a silicon waveguide to selectively modulate and direct light by carrier refraction. An electrooptic phase modulator and several 2.times.2 electrooptic switches are described. The devices are particularly useful for manipulating light signals in the 1.3-1.6 micron range.

Abstract: An electrically controlled integrated optical switch having a body made up entirely of crystalline silicon. More specifically, the body has a pair of channel waveguides intersecting in an X-like configuration forming therein an intersection crossover region. A first electrode is positioned on the intersection crossover region and a second electrode is positioned on the bottom of the body opposite the intersection crossover region. A controllable current/voltage source is electrically connected to the electrodes in order to alter the index of refraction of the intersection crossover region by carrier injection in order to selectively switch optical signals between diverging waveguides.

Abstract: A fiber optic device 50 designed to steer the radiation beam of a phased-array antenna 10 has been demonstrated. A radio frequency (RF) signal is generated via photomixing at the output of a single-mode fiber optic interferometer. The phase of the electrical signal is shifted over several cycles in direct proportion to a voltage applied to an optical modulator 34, 60. The modulator consists of a Pockels-type optical phase modulator located in one arm of the heterodyne interferometer. Rapid changes in RF phase are feasible. A miniature low-voltage version of the device 50, 72, based upon integrated optics, has been devised.

Abstract: An electrically controlled integrated optical switch having a body made up entirely of crystalline silicon. More specifically, the body has a pair of channel waveguides intersecting in an X-like configuration forming therein an intersection crossover region. A first electrode is positioned on the intersection crossover region and a second electrode is positioned on the bottom of the body opposite the intersection crossover region. A controllable current/voltage source is electrically connected to the electrodes in order to alter the index of refraction of the intersection crossover region in order to change the amount of optical cross coupling of light between the intersecting waveguides.

Abstract: A mode dependent, optical time delay system for electrical signals having a highly multi-mode optical fiber having a step index profile in optical alignment with an optical source which is capable of converting an incoming electrical signal into an optical signal. By incorporating within the system a number of different components to alter or control the mode angles of the incoming optical signal, the resultant optical output signal is time delayed as it propagates through the optical fiber. This optical output signal is thereafter converted into an electrical output signal which is also time delayed in direct relation to the mode angle of the optical signal propagating through the optical fiber.

Abstract: An optically controlled integrated optical switch having a body made up of entirely crystalline silicon. More specifically, the body has a pair of channel waveguides intersecting at an X-like configuration forming therein an intersection crossover region. An electrically controlled optical source is positioned over the crossover region to shine intense, short wavelight on the crossover region in order to generate numerous electron-hole pairs in the waveguide material. These charge carriers alter the refractive index of the intersection region. A controllable current source is used to adjust the optical output power of the optical source. This, in turn, changes the amount of optical cross coupling of light between the intersecting waveguides.

Abstract: A guided-wave optical power divider having a body made entirely of crystalline silicon and wherein the crossover region of intersecting light guiding channels is doped with a predetermined amount of impurities. By appropriate use of impurities it is possible to create permanent optical power dividers in which a light beam is preselectively directed to follow a preselected path.

Abstract: A length dependent, optical time delay/filter device for electrical signals having a single integrated optical switching circuit and only two optical time delay components connected thereto. The optical time delay components are each made up of a plurality of optical fibers of varying lengths. Depending upon which fibers an optical signal (converted from an incoming electrical signal) passes through determines the time of travel of the optical signal through the device. This optical signal is then converted back into an electrical output signal which is, as a result thereof, time delayed/filtered.

Abstract: A wavelength dependent, tunable, optical time delay system for electrical signals having a conversion/tuning unit for converting an incoming electrical signal into an optical signal as well as selectively varying the wavelength of the optical signal; a single-mode, high dispersion optical fiber for receiving the optical signal and through which the optical signal propagates at a speed dependent upon its wavelength; and a detector/converter for converting the optical signal back to an electrical signal. By utilizing a separate preselected electronic control-signal fed to the conversion/tuning unit, the wavelength of the optical signal entering the fiber can be varied over a preselected wavelength band of interest. By selectively varying the wavelength of the optical signal, the electrical signal can be effectively and rapidly time delayed as desired in response to the electronic signal.

Abstract: A battery powered optical sensor, capable of functioning for a period of time approximately equal to the shelf life of the battery, utilizes an LED driven by an optical transducer and biased by the battery at a level that exceeds the shot noise level of the LED by the dynamic range of the sensor.