Abstract: A method and apparatus for providing optical 3R regeneration involving: 1) generating an encoded optical clock signal from at least an optical signal; 2) introducing the encoded clock signal into a delay interference section of a regenerator such that an amplitude modulated clock signal is produced; andoutputting the amplitude modulated clock signal wherein the output amplitude modulated clock signal preserves information present within the input optical signal.

Abstract: A tunable laser incorporating an N1×N2 chirped waveguide grating router that has N1N2 wavelengths, accessible in a digitally rapid manner, and using only N1+N2+1 semiconductor optical amplifiers. Through the use of chirp, free-spectral range of the router can be significantly less than the channel span. The exemplary laser has N1=5, N2=8, a channel spacing of 100 GHz, and the router free-spectral range is only 20 channels.

Abstract: A method and apparatus for establishing multimedia calls over an intelligent telecommunications network in which the calls are requested through an internetwork of client computers and server computers and the internetwork of client computers and server computers is further connected to the intelligent telecommunications network. The method involves: 1) a caller generating a request for a call utilizing the internetwork to initiate the request; 2) delivering multimedia and/or audiovisual presentations(s) to the caller via the internetwork and/or public switched telephone network (PSTN); and 3) completing a circuit switched telephone call between the caller and a destination user subsequent to the delivery of the presentations(s) wherein the call is placed from within the intelligent network itself. In this manner, one or more multimedia advertisements or other presentations are delivered to the originating caller before completion of the requested call.

Abstract: An optical device having an array of substantially equal-length optical waveguides. Each one of the optical waveguides includes one or more straight segments, one or more curved segments, and optionally, one or more transition segments. According to the invention, the sum of the lengths of the straight segments in each of the waveguides is substantially equal. Similarly, the sum of the lengths of the curved segments in each of the waveguides may be substantially equal as well. Finally, the sum of the lengths of optional transition segments in each of the waveguides may also be substantially equal. Advantageously, the device exhibits relative lengths that are robust to fabrication errors and have low polarization sensitivity.

Abstract: In a waveguide grating router, a predetermined composite transmission spectrum output is achieved by eliminating loss imbalances through the use of variable loss elements. The variable loss elements are introduced to the waveguide grating router's waveguide ports, such that the loss of a transmitted signal is independent of wavelength. The waveguide grating router includes at least one input waveguide and a plurality of output waveguides. The variable loss element is introduced to a predetermined group of output waveguides to produce a predetermined composite amplitude spectrum of the output signals. To provide a predetermined composite amplitude output spectrum, the variable loss elements may be implemented in a variety of ways, including a method of varying the cross-sectional areas of the router's waveguide ports to introduce more loss.

Abstract: A waveguide grating router having an improved passband flatness with lower loss is provided that includes a first optical coupling device having at least one input port, at least one mode converter, and P output ports, where P>2. A second optical coupling device is also provided that has P input ports, least one output port, and at least one mode converter. P optical paths couple the input port of the first optical coupling device to the output port of the second optical coupling device. The mode converters control the magnitudes of various transmission coefficients contributed by the optical paths of the router. The phases of the various contributions are determined by the optical path lengths, and these lengths are chosen so that certain contributions are opposite to other contributions.

Abstract: A method of aligning, placing, and attaching an optical fiber directly to an electronic, complementary, metal-oxide-semiconductor (CMOS) chip that uses alignment features defined during the CMOS fabrication. The method involves the steps of: i) defining, during the fabrication of an electronic CMOS device, one or more shallow grooves upon the device substrate; ii) disposing an optical fiber within the defined groove(s); and iii) securing the optical fiber within the groove(s). Advantageously, the method may be practiced using a variety of fabrication techniques and apparatus that are compatible with conventional CMOS devices.

Abstract: A high-capacity, chirped-pulse wavelength-division multiplexed communications apparatus and method in which a chirped-pulse, wavelength-division multiplexed signal is further optically multiplexed thereby enhancing bit rates per channel. A multifrequency optical source for supplying an optical signal having a number of wavelength division multiplexed (WDM) channels; a power splitter for splitting the optical signal from the multifrequency source into a number of signals; a number of time delay lines, for delaying each one of the signals independently; a number of data encoding modulators for modulating each one of the delayed signals; and a power combiner for combining the number of delayed, modulated signals into a single signal such that the multifrequency optical source signal is multiplexed by a desired amount.

Abstract: A Wavelength-Division-Multiplexer (WDM) programmable add/drop using an interleave-chirped waveguide grating router and phase shifters in a reflective arrangement. Experimental results of a 16.times.100-GHz version in InP is presented.

Abstract: Low-noise, bidirectional communications in a fiber optic cable is achieved by coupling a first end of the cable to an optical power source having an inherently broad spectral width. A second end of the cable is coupled to an optical detector having a detector bandwidth, such that the bandwidth of the optical power source is greater than the detector bandwidth. When the bandwidth of the optical power source is large compared to the bandwidth of the detector, the beat frequencies resulting from coherent Rayleigh noise fall outside the bandwidth of the detector and are not detected.

Abstract: Providing a compositional image of an object in real time is accomplished by illuminating the object with a waveform comprising pulses of electromagnetic radiation in the terahertz frequency range and measuring the relative time delays of pulses reflected by the object to determine the positions of dielectric interfaces in the object. According to a further embodiment, the waveform includes one or more pulses of terahertz radiation, each pulse having a duration in the range of approximately 10 to 10,000 femtoseconds.

Abstract: A display rerouting apparatus reroutes a displayed image from an image source in a display module for providing a redirected angular visibility for the displayed image. In an illustrative embodiment, the display rerouting apparatus includes a base panel having a rectangular opening or widow for positioning atop of a display module in communication equipment, a rear panel having a one-way reflective mirror positioned in a rectangular opening in this rear panel, and a front panel having a two-way reflective mirror positioned in a rectangular opening in this front panel. Both the rear and front panels are respectively hingeably attached at their lower edges to the rear and front edges of the base panel for facilitating the use of the rerouting apparatus on different types of communication. In operation, the image from the display module is projected through the base of the apparatus onto the two-way reflective mirror.

Abstract: A current driver circuit for a vertical cavity surface emitting laser (VCSEL), flip-chip bonded to a CMOS device. In a preferred embodiment, the circuit includes only two transistors. Specifically, a P-channel metal-oxide semiconductor (PMOS) source supplies a current under the control of a tuning voltage (Vtune) while an N-channel metal-oxide semiconductor (NMOS) transistor acts as a high-speed current shunt that modulates the current flowing through the VCSEL, and hence its emitted power.

Abstract: A method for determining the optimal design of a gain equalization filter (GEF) used in optical fiber amplifiers. The method is suitable for erbium-doped fiber amplifiers (EDFA) that are widely used in wavelength-division-multiplexed (WDM) optical communication systems and networks.

Abstract: A wide band optical amplifier employing a split-band architecture in which an optical signal is split into several independent sub-bands which then pass in parallel through separate branches of the optical amplifier. Each branch may be optimized for the sub-band that traverses it. The independent sub-bands are combined before output, resulting in a broad band, high efficiency amplifier. Alternative, hybrid split-band amplifiers are described. As a result of their desirable characteristics, these wide band optical amplifiers may be used in dense WDM communications systems.

Abstract: A time-domain signal processing system for displaying, classifying, and recognizing temporal and spectral features in terahertz waveforms returned form materials. Specifically, novel techniques are described for classifying and analyzing the free induction decay exhibited by gases excited by far-infrared (terahertz) pulses. Illustratively, a simple geometric picture may be used for the classification of the waveforms measured for unknown gas species and gas mixtures.