Abstract: An improved optical rotary joint is achieved by transmitting information in the form of an optical signal from a part of the de-spun portion outside the rotational axis to the spun portion, or vice versa, thereby creating a continuous communication path 360.degree. about the rotational axis. The optical rotary joint includes either a plurality of transmitters on one portion and a detector on the other portion, or a transmitter on one portion and a plurality of detectors on the other portion. In the former, the transmitters are controlled such that only the transmitters transmitting optical signals that will be detected by the detector at a given point in the rotation are activated and the remaining transmitters are deactivated. In the latter, the detectors are controlled such that only the detectors detecting the optical signal transmitter by the transmitter at a given point in the rotation are activated and the remaining detectors are deactivated.

Abstract: A splice protection device is constructed for acceptance of a pair of light waveguides, with the splice location being optimally sealed by elastic holders having an adhesive film. The elastic splice protection device can be utilized in a bent shape, so that the dimensions of a cassette and other receptacle devices can be designed to be smaller.

Abstract: In accordance with the invention, an optical pulse compressor comprises a pulse source, a section of nonlinear optical waveguide including a periodic structure, such as a Bragg grating, for providing positive dispersion and a section of linear optical waveguide including a negative dispersion component. The nonlinear waveguide should have a second order index N.sub.2 at least ten times the second order index N.sub.2 ' of the linear waveguide. The nonlinear waveguide is preferably chalcogenide fiber, with a Bragg grating photoinduced into the core. Because the grating is 4-5 orders of magnitude more dispersive than standard optical fiber, the length of the nonlinear waveguide section can be scaled down to a few centimeters with accompanying reduction of deleterious processes. Modeling suggests that compression factors of 5 with an initial 60 ps pulse are achievable with grating lengths of about 20 cm.

Abstract: A one dimensional series of complex coupled (gain or loss coupled) DFB semiconductor lasers is disclosed. Each laser comprises a multiple quantum well active region and a complex coupled grating having corrugations along a cavity length direction formed by periodically etching grooves through the active region. The grating has a period comprising a first section and a second section, wherein substantially all quantum wells are etched away from the second section providing no substantial photon generation in the second section. The depth of etching is defined so as to provide a substantial insensitivity of each laser to the external feedback and random facet variations and to ensure no substantial interaction between lasers in the series. The lasers in the series may further comprise means for tuning laser wavelengths around corresponding lasing modes and/or means for switching between the lasing modes.

Abstract: A highly efficient channel drop filter. The filter employs a coupling element including a resonator-system between two waveguides, which contains at least two resonant modes. The resonator-system includes one or more interacting resonant cavities which in addition to being coupled to the waveguides, can also be coupled directly among themselves and indirectly among themselves via the waveguides. Each component of the coupling element can be configured or adjusted individually. The geometry and/or dielectric constant/refractive index of the resonator-system are configured so that the frequencies and decay rates of the resonant modes are made to be substantially the same. The filter can achieve 100% signal transfer between the waveguides at certain frequencies, while completely prohibiting signal transfer at other frequencies. In exemplary embodiments, the filter is configured with photonic crystals.

Abstract: An improved optical fiber connection system comprises an attenuator element fabricated with an inherently elastomeric material, preferably a silicone elastomer. Silicone elastomers are particularly preferred for fabricating attenuator elements as they may be index-matched to optical transmission fibers, have a high creep modulus, exhibit relatively constant mechanical properties over a broad range of temperatures, and are reliable upon exposure to varied environmental conditions. Preferably, a disc-like attenuator element is punch-cut from a sheet of a silicone elastomer and inserted into the sleeve of an optical connector apparatus adjacent the end portion of an optical fiber to provide a simplified method of fabrication. Alternatively, the silicone attenuator element may be fabricated by liquid injection molding technology. The approximate reflectance of the inventive silicone attenuators at wavelengths of about 1310 nm measured at 23.degree. C. is less than -50 dB.

Abstract: An optical fiber ribbon is disclosed. The optical fiber ribbon comprises a plurality of optical fibers arranged in a parallel planar array, the planar array being further defined by first and second planar sides spanning between first and second ends. A matrix material coating envelops the optical fibers so as to bond the optical fibers together in the parallel planar array. The matrix material coating forms a first substantially planar surface section spanning the first planar side of the planar array of optical fibers. A second substantially planar surface section spans the second planar side of the planar array of optical fibers. A first hinge section bridges the first and second substantially planar surface sections at the first end of the planar array and a second hinge section bridges the first and second substantially planar surface sections at the second end of the planar array.

Abstract: A semiconductor laser drive circuit for supplying an electric current to a semiconductor laser includes a laser power supply which supplies an electric current of a positive or negative voltage to the semiconductor laser, an operational amplifier which is driven by a positive amplifier power supply and a negative amplifier power supply, and a current control element which controls the amount of electric current flowing into the semiconductor laser according to the output of the operational amplifier. A sequence circuit causes one of the amplifier power supplies, which one is reverse in polarity as the laser power supply, to start first and then causes the other amplifier power supply to start after the former amplifier power supply achieves a steady voltage.

Abstract: The reinforced optical fiber cable of unitube structure comprises a protective tube for protecting optical fibers, a reinforcing layer, and reinforcing cords, together with an outer sheath around the protective tube. In the cable the protective tube is of corrugated tubular structure. Such a cable is particularly suited for use as a long distance transmission cable.

Abstract: In an optical modulation method a wave to be modulated and an optical control wave are injected simultaneously and colinearly into the same waveguide formed in a semiconductor diode that is reverse-biased so that the waveguide and the diode constitute the semiconductor part of an electro-absorption modulator. The wavelength of the control wave is shorter than that of the wave to be modulated. The impedance at the terminals of the diode is sufficiently high to enable amplitude modulation of the control wave to be transferred to the wave to be modulated. Applications include fiber optic telecommunication systems, in particular for resynchronizing solitons.

Abstract: An optical modulator that modulates light through the semiconductor substrate through the back side of a flip chip packaged integrated circuit. The optical modulator of the present invention enables integrated circuit signals to be extracted through the back side of the semiconductor substrate. In one embodiment, an optical modulator is disposed within a flip chip packaged integrated circuit die. The optical modulator includes a deflector and a diffraction grating. An infrared light beam is directed through the back side of a silicon substrate of the integrated circuit die, deflected off the deflector through the diffraction grating and back out the back side of the integrated circuit die. The diffraction grating modulates the phase of a portion of the deflected light beam in response to an integrated circuit signal. A resulting diffraction interference occurs between the phase modulated portions and non-phase modulated portions of the deflected light beam.

Abstract: An optical telecommunications system node terminates a plurality of optical cable routes. Each of the optical cable routes includes a traffic route and a restoration route. The node includes a plurality of traffic wavelength division multiplexers and a plurality of restoration wavelength division multiplexers. A traffic wavelength division multiplexer is connected to each traffic route and a restoration wavelength division multiplexer is connected to each restoration route. The node includes a plurality of optical cross connect layers. Each optical cross connect layer includes a connection to each of the traffic wavelength division multiplexers and to each of the restoration wavelength division multiplexers.

Abstract: A method and an apparatus providing an optical input/output bus in an integrated circuit by optically routing input/output signals between integrated circuit nodes. In one embodiment, input/output signals are optically routed back and forth through the back side semiconductor substrate of a flip chip packaged integrated circuit die. An optical assembly used to generate and direct the light beams of the optical bus may be included within a heat sink thermally coupled to the back side silicon substrate of the integrated circuit die. Alternatively, the optical assembly may be embedded into the back side silicon substrate of the integrated circuit die. In operation, a light beam is directed through the back side semiconductor substrate onto an optical modulator. The optical modulator modulates and deflects the light beam. The deflected light beam is routed to a deflector that directs the modulated and deflected light beam through the back side semiconductor substrate onto an optical demodulator.

Abstract: The invention provides an optical switch and modulator which uses a closed loop optical resonator. The optical resonator is a dielectric cavity whose primary function is to store optical power. Various structures are possible, and a particularly advantageous one is a ring shaped cavity. The wavelength response at the output port of a ring resonator side coupled to two waveguides is determined by the details of the resonator, and the coupling between the resonator and the waveguides. By coupling to adjacent resonators, the modulator response can be improved over that of a single resonator. One such improvement is in modulator efficiency, which is defined as the ratio of the change in optical intensity at the output, to a change in absorption in the ring waveguides. Absorption is used for switching and modulation without incurring significant optical attenuation. Another improvement involves making the resonance insensitive to small deviations in wavelength or index change.

Abstract: A method and an apparatus providing optical input/output in an integrated circuit. In one embodiment, optical modulators and demodulators, which are coupled to integrated circuit input/output nodes, are disposed on or within the back side semiconductor substrate of a flip chip packaged integrated circuit. Since a flip chip packaged integrated circuit die is utilized, full access to the optical modulators and demodulators is provided from the back side of the integrated circuit die for optical input/output. In one embodiment, a heat sink including a light source and an optical assembly is thermally and optically coupled to the back side of the integrated circuit die. A light beam is directed to the optical modulators and the deflected modulated light beam is routed and directed to the optical demodulators to realize optical input/output. In one embodiment, infrared light may be utilized such that the optical modulators and demodulators are disposed within a silicon semiconductor substrate.

Abstract: The fiberoptic block in accordance with the present invention has an input end face constituted by a combination of a plurality of surfaces each of which is inclined at a slant angle .alpha. by which disturbing light from within the air can be eliminated, whereby an irregularity image with a high contrast can be emitted as usual. Also, it has an output end face perpendicular to the axis of each unit fiber. Accordingly, when the output end face is butted against and secured to an input face of a photodetector, the irregularity image is made incident on the input face of the photodetector so as to be substantially perpendicular thereto, thus allowing a bright irregularity image to be attained. Further, since this fiberoptic block has a form extending from the output end face in a direction perpendicular thereto, it can be attached to the photodetector relatively easily with a high precision.

Abstract: In accordance with the invention, an optical multiplexer includes at least one reconfigurable add-drop unit that can add-drop one channel out of a large set by switching the light path through one of a set of fixed add-drop filters. Reconfiguration is done by switching from the add-drop filter path to a bypass path, changing to a different add-drop filter and then switching back. The phase delay of the bypass path is adjusted to maintain nearly maximum transmission during switching. The selection among add-drop filters is done by sliding an integrated optic chip with the set of add-drop filters between input and output waveguides. The reconfigurable add-drop multiplexer unit is latchable, passive between reconfigurations, and has low intrinsic insertion loss. Plural units in series can add/drop plural channels.

Abstract: A method for reducing the stress in a fiber by varying the curvature of a fiber disposed on a cylindrical surface, so that the first end of the fiber is clamped to the cylindrical surface and the second end of the fiber is moveably fastened to the cylindrical surface. The method extends the fiber around a portion of the cylinder, provides a fastening element so as to control the location of the second end of the fiber on the cylindrical surface and adjusts the curvature of the fiber so that the total curvature of the fiber remains substantially constant over the entire length of the fiber.

Abstract: A bracket assembly is provided for managing and strain relieving jumpers exiting an optical hardware cabinet. The bracket has a length portion and at least one fanning finger block mounted thereon to define a line of routing spaces for jumpers. The bracket further has at least one tie portion located at an end of the length portion and extending laterally of the length portion defining a free edge. The tie portion defines holes suitable for threading a cable tie therethrough. The tie portion is located relative to the fanning finger blocks such that jumpers routed through the fanning fingers can be gathered together over the tie portion and secured thereto with a cable tie threaded through one of the holes. The bracket has a mounting portion extending downward from the bracket to provide a clearance space to allow for threading of a cable tie through the hole.

Abstract: A light guide plate is provided including a first lens portion comprising a plurality of recessed or projected lenticular unit lenses formed of the same resin as that of the light guide plate on a light emission surface. The plurality of lenticular unit lenses in the first lens portion are triangular prism portions whose respective vertexes have an angle of 125.degree. to 165.degree. and are so arranged that their respective ridge lines are nearly parallel to each other. Such construction makes it possible to set the number of lenticular lens sheets used to one or to further eliminate the necessity of the lenticular lens sheets, so that the cost of parts and the fabrication cost of the light guide plate can be reduced.