Abstract: A delta-sigma modulator has a first node at which is produced a difference signal equal to the difference in magnitude between a continuous time analog signal and an analog feedback signal generated from a digital output signal; an integrator, coupled to the first node, to integrate the difference signal, thereby producing a first integrated signal; a photonic sampler, coupled to the integrator, to sample the first integrated signal, thereby producing a sampled integral signal; a quantizer, coupled to the sampler, to quantize the sampled integral signal, thereby producing the digital output signal; wherein an output of the quantizer is coupled to the first node through a digital to analog converter.

Abstract: A lead-frame for connecting and supporting an integrated circuit chip with a chip accommodating zone with inwardly extending ears for supporting the chip including minimum shoulder area, and having open crack and delamination stopping regions.

Abstract: A RF amplification system which includes a RF modulation unit fed by an optical carrier and an RF input signal, the modulation unit modulating the RF input signal onto the optical carrier to produce a modulated RF optical signal; an array of optical amplifiers coupled to the modulation unit for receiving and amplifying the modulated RF optical signals; and a detecting unit having at least one photodetector coupled to the array of optical amplifiers for receiving and detecting the modulated RF optical signals, the at least one photodetector producing an amplified RF output in response thereto.

Abstract: A Delta-Sigma Analog-to-Digital Converter (ADC) that can have a very high sampling rate (over 100 GHz) and which is preferably optically sampled to help achieve its very high sampling rate. The sampling rate can be many times higher than the regeneration speed of the electronic quantizers used in the ADC.

Abstract: An agile spread spectrum waveform generator comprises a photonic oscillator and an optical heterodyne synthesizer. The photonic oscillator comprises a multi-tone optical comb generator for generating a series of RF comb lines on an optical carrier. The optical heterodyne synthesizer includes first and second phase-locked lasers; the first laser feeding the multi-tone optical comb generator and the second laser comprising a rapidly wavelength-tunable single tone laser whose output light provides a frequency translation reference. A photodetector is provided for heterodyning the frequency translation reference with the optical output of the photonic oscillator to generate an agile spread spectrum waveform.

Abstract: An optoelectronic device and a method of making same. The optoelectronic device comprises a substrate, at least one dielectric waveguide in the substrate, and at least one active semiconductor layer physically bonded to the substrate and optically coupled to the at least one dielectric waveguide in the substrate, the at least one active semiconductor layer being able to generate light, detect light, amplify light or otherwise modulate amplitude or phase of light.

Abstract: A multi-tone photonic oscillator comprises a laser; an optical modulator coupled to the laser; and a delay line and a photodetector coupled to the optical modulator for generating a delayed electrical signal representation of the output of the optical modulator; wherein the optical modulator being responsible for the delayed electrical signal for generating multiple tones where the frequency intervals of the tones is a function of the amount of delay imposed by the delay line.

Abstract: A waveform synthesizer comprising for synthesizing RF lightwave waveforms in the optical domain. These waveforms are constructed by generating their constituent Fourier frequency components or tones and then adjusting the amplitudes of those frequency components or tones. The apparatus includes: a RF-lightwave frequency-comb generator; and a multi-tone, frequency selective amplitude modulator coupled to the RF-lightwave frequency-comb generator for generating a continuous-wave comb comprising a set of RF tones amplitude modulated onto a lightwave carrier.

Abstract: A photonically sampled analog-to-digital converter using parallel channels of sampling and quantizing. The parallel combination achieves cancellation of the spurs that result from the nonlinear transfer function of the samplers. The samplers feed a dual-detector optoelectronic receiver that has differential inputs for suppression of laser intensity noise. The outputs of the multiple photonic samplers are averaged to reduce the effects of shot or thermal noise from the optoelectronic receiver of a sampler. The errors produced by the quantization process can be reduced by using a delta-sigma modulator-based analog-to-digital convertor as the quantizer which provides noise-spectrum shaping and filtering.

Abstract: An apparatus and method for photonically sampling an analog signal and encoding the photonically sampled signal. The two interferometer arms of a Mach-Zehnder interferometer section are directly coupled to the dual input ports of a directional coupler switch section. Optical pulses transmitted through the interferometer arms are phase shifted in proportion to an analog signal applied at the electrical input port of the Mach-Zehnder interferometer section. The phase-shifted pulses in each interferometer arm are coupled in the directional coupler switch section and are directed to the dual output ports of the directional switch section based upon the binary code applied to the electrical input port of the directional coupler switch section. The directional switch section has an optical length designed to provide a net phase shift of 3&pgr;/4.

Abstract: An application-specific rf optoelectronic integrated circuit having a generic chip member and a defining substrate in communication with at least one generic chip member. The generic chip member contains passive building block components that are independent from each other and being connected by paths external to the generic chip member. The external connection paths are defined by a defining substrate member having passive components for providing optical and electrical interconnection between selected building block components on the generic chip member to define the specific function of the integrated circuit. It is possible to use the same design of the generic chip for several applications merely by altering the interconnect paths on a defining substrate.

Abstract: A method and apparatus for aligning an optical fiber to an optoelectronic element. The optical fiber and optoelectronic element are attached to a base. The base is made from a first crystallographic orientation material, and a lens is made from a second crystallographic orientation material. The lens is aligned to the base using the crystallographic orientations, and the optical fiber and optoelectronic element are aligned to the base/lens assembly.

Abstract: A laser system and method for self-injection locking. The system includes a laser having a laser output at a frequency &ohgr;o. An optical port provides a portion of the laser output at the port and a modulator, coupled to the port, is driven by a RF signal at a frequency &ohgr;m generates two sidebands at &ohgr;o±&ohgr;m. A filter passes one of the two sidebands; and an optical path couples an output of the filter to the laser for injection locking.

Abstract: A lead-frame for connecting and supporting an integrated circuit chip with a chip accommodating zone with inwardly extending ears for supporting the chip including minimum shoulder area, and having open crack and delamination stopping regions.

Abstract: A photonically sampled analog-to-digital converter using parallel channels of sampling and quantizing. The parallel combination achieves cancellation of the spurs that result from the nonlinear transfer function of the samplers. The samplers feed a dual-detector optoelectronic receiver that has differential inputs for suppression of laser intensity noise. The outputs of the multiple photonic samplers are averaged to reduce the effects of shot or thermal noise from the optoelectronic receiver of a sampler. The errors produced by the quantization process can be reduced by using a delta-sigma modulator-based analog-to-digital convertor as the quantizer which provides noise-spectrum shaping and filtering.

Abstract: An integrated optical transmitter includes a modulator drive circuit in communication with a modulator, and a laser drive circuit in communication with a laser. The modulator receives laser light from the laser and modulation control signals from the modulator drive circuit, and outputs modulated optical signals in a direction normal to the substrate surface. The transmitter is integrated by securing the laser to the modulator using flip chip technology. The laser includes a vertical cavity, and is optically aligned with the horizontal coupling surface of the modulator during the flip chip process.

Abstract: A method and apparatus for aligning an optical fiber to an optoelectronic element. The optical fiber and optoelectronic element are attached to a base. The base is made from a first crystallographic orientation material, and a lens is made from a second crystallographic orientation material. The lens is aligned to the base using the crystallographic orientations, and the optical fiber and optoelectronic element are aligned to the base/lens assembly.

Abstract: A method for fabrication of a solder bump, comprising applying preferably an insulating film, followed by applying a multilayer underbump metallization, a layer of a photoresist, and a thin layer of titanium on a substrate containing, preferably, III-V semiconductor circuits. The multilayer UBM pad, preferably comprising a 0.02 to 0.05 micrometer thick layer of titanium, a 0.5 to 1.0 micrometer thick layer of nickel and a 0.1 to 0.2 thick layer of gold. The protective film with the thickness of preferably 0.5 to 40 micrometer comprises a photoresist. After the solder has been electroplated, the protective film is removed, preferably by dry etching or with a solvent. The titanium film serves a dual function of being a membrane for electroplating of the solder and of being a non-wettable dam for wetting back of the plated solder. The titanium film with the thickness of 200 to 1,000 Angstroms is preferably deposited by evaporation.

Abstract: A method for fabrication of a solder bump, comprising applying preferably an insulating film, followed by applying a multilayer underbump metallization, a layer of a photoresist, and a thin layer of titanium on a substrate containing, preferably, III-V semiconductor circuits. The multilayer UBM pad, preferably comprising a 0.02 to 0.05 micrometer thick layer of titanium, a 0.5 to 1.0 micrometer thick layer of nickel and a 0.1 to 0.2 thick layer of gold. The protective film with the thickness of preferably 0.5 to 40 micrometer comprises a photoresist. After the solder has been electroplated, the protective film is removed, preferably by dry etching or with a solvent. The titanium film serves a dual function of being a membrane for electroplating of the solder and of being a non-wettable dam for wetting back of the plated solder. The titanium film with the thickness of 200 to 1,000 Angstroms is preferably deposited by evaporation.

Abstract: A method and apparatus for aligning an optical fiber to an optoelectronic element. The optical fiber and optoelectonic element are attached to a base. The base is made from a first crystallographic orientation material, and a lens is made from a second crystallographic orientation material. The lens is aligned to the base using the crystallographic orientations, and the optical fiber and optoelectronic element are aligned to the base/lens assembly.