Abstract: An apparatus for analyzing, identifying or imaging an target including first and second laser beams coupled to a pair of photoconductive switches to produce CW signals in one or more bands in a range of frequencies greater than 100 GHz focused on and transmitted through or reflected from the target; and a detector for acquiring spectral information from signals received from the target and using a multi-spectral heterodyne process to generate an electrical signal representative of some characteristics of the target. The lasers are tuned to different frequencies and a frequency shifter in the path of one laser beam allows the terahertz beam to be finely adjusted in one or more selected frequency bands.

Abstract: A drive apparatus for a concentrator photovoltaic array including a gearbox case, a motor body housed within the gearbox case and a motor shaft coupled to and extending though a motor bearing of the motor body and having an axis of rotation. A front shaft mount bearing is coupled to one distal end of the motor shaft and a rear shaft mount bearing coupled to the other distal end of the motor shaft, and the front and rear shaft mount bearings are constrained by the gearbox case. A driver gear can be coupled to the motor shaft to drive the photovoltaic array. The front and rear shaft mount bearings transfer loads from the motor bearing to the gearbox case.

Abstract: An apparatus for analyzing, identifying or imaging an target including first and second laser beams coupled to a pair of photoconductive switches to produce CW signals in one or more bands in a range of frequencies greater than 100 GHz focused on and transmitted through or reflected from the target; and a detector for acquiring spectral information from signals received from the target and using a multi-spectral heterodyne process to generate an electrical signal representative of some characteristics of the target. The lasers are tuned to different frequencies and a frequency shifter in the path of one laser beam allows the terahertz beam to be finely adjusted in one or more selected frequency bands.

Abstract: A method of fabricating a semiconductor laser device by forming a semiconductor structure at least part of which is in the form of a mesa structure having a flat top. The steps include depositing a passivation layer over the mesa structure, forming a contact opening in the passivation layer on the flat top of the mesa structure; and depositing a metal contact portion, with the deposited metal contact portion contacting the semiconductor structure via the contact opening. The contact opening formed through the passivation layer has a smaller area than the flat top of the mesa structure to allow for wider tolerances in alignment accuracy. The metal contact portion comprises a platinum layer between one or more gold layers to provide an effective barrier against Au diffusion into the semiconductor material.

Abstract: An apparatus for analyzing, identifying or imaging an target including first and second laser beams coupled to a pair of photoconductive switches to produce CW signals in one or more bands in a range of frequencies greater than 100 GHz focused on and transmitted through or reflected from the target; and a detector for acquiring spectral information from signals received from the target and using a multi-spectral heterodyne process to generate an electrical signal representative of some characteristics of the target. The lasers are tuned to different frequencies and a frequency shifter in the path of one laser beam allows the terahertz beam to be finely adjusted in one or more selected frequency bands.

Abstract: A method comprising forming two or more frames from a first wafer, forming two or more etalons from a second wafer, disposing a resistive thermal device on each of the two or more frames, dicing the first wafer and the second wafer, and bonding each of the frames to a corresponding one of the etalons to form optical subassemblies of optical filters.

Abstract: A tunable laser transmitter configured in a small package subassembly coupled to a printed circuit board such as an ITLA assembly. The tunable laser transmitter includes a housing with a volume formed by exterior walls. An electrical input interface is positioned at the first end of the housing. An optical output interface is positioned at the second end of the housing and configured to transmit a modulated optical beam.

Abstract: A multimode interference splitter/combiner that includes a monolithic device for photonically coupling an input optical waveguide to first and second output optical waveguides. The input waveguide may be optically coupled to a first end of a MMI portion, while the first and second output waveguides may be optically coupled to a second end of the MMI portion. The input waveguide is coupled to a planar facet of the MMI portion so that the input waveguide may have a propagation axis that is oriented at an angle with respect to the planar facet of the MMI portion. A desired splitting ratio may be achieved by adjusting the angle between the input waveguide and the MMI portion.

Abstract: An optical transmitter for generating a modulated optical signal to be transmitted over fiber optical link. The transmitter includes: an optical source for producing an optical signal; an optically linearized modulator (OLM) as external modulator for modulating the optical signal produced by the optical source with an information carrying signal. The external modulator includes a first input port for receiving a first DC bias signal, and a second input port for receiving a second DC bias signal. The optical transmitter further includes a pilot tone generator for generating a first pilot signal to be applied to the first input port and a second pilot signal to be applied to the second input port. The first and second pilot signals are capable of producing distortion products in the modulated optical signal.

Abstract: An apparatus for analyzing, identifying or imaging an target including first and second laser beams coupled to a pair of photoconductive switches to produce CW signals in one or more bands in a range of frequencies greater than 100 GHz focused on and transmitted through or reflected from the target; and a detector for acquiring spectral information from signals received from the target and using a multi-spectral heterodyne process to generate an electrical signal representative of some characteristics of the target. The lasers are tuned to different frequencies and a frequency shifter in the path of one laser beam allows the terahertz beam to be finely adjusted in one or more selected frequency bands.

Abstract: A tunable laser configured in a small package coupled to a printed circuit board. The tunable laser includes a housing with a volume formed by exterior walls. An electrical input interface is positioned at the first end of the housing. An optical output interface is positioned at the second end of the housing and configured to transmit a continuous wave optical beam. A beam splitter and photodiode is disposed in the path of the laser beam for determining the emitted intensity of the laser beam, and an optical isolator is positioned downstream of the beam splitter to prevent the incoming light from the beam splitter from reflecting back though the beam splitter and into the cavity of the laser.

Abstract: An optical communication system having a transmitter in which a pair of optical signals having different frequencies are modulated using a duobinary encoding scheme, and then multiplexed using polarization division multiplexing. Advantageously, the frequency difference between the two signals can be less than the data rate conveyed by each signal, resulting in a narrow spectral bandwidth, while still allowing demultiplexing at a receiver using simple bandpass filters and without the need of any form of polarization tracking. A receiver has a beam splitter for splitting the received optical signal into two portions which are each directed, via respective bandpass filters centred at slightly different frequencies, to respective detectors. Advantageously, the frequency difference between the frequencies at which the bandpass filters are centred can be less than the data rate of a detected signal.

Abstract: A method of fabricating a semiconductor laser device by forming a semiconductor structure at least part of which is in the form of a mesa structure having a flat top. The steps include depositing a passivation layer over the mesa structure, forming a contact opening in the passivation layer on the flat top of the mesa structure; and depositing a metal contact portion, with the deposited metal contact portion contacting the semiconductor structure via the contact opening. The contact opening formed through the passivation layer has a smaller area than the flat top of the mesa structure to allow for wider tolerances in alignment accuracy. The metal contact portion comprises a platinum layer between one or more gold layers to provide an effective barrier against Au diffusion into the semiconductor material.

Abstract: According to one embodiment, the present application includes a tunable laser configured in a small package. The tunable laser includes a housing with a volume formed by exterior walls. An electrical input interface is positioned at the first end of the housing and configured to receive an information-containing electrical signal. An optical output interface is positioned at the second end of the housing and configured to transmit a continuous wave optical beam. A tunable semiconductor laser is positioned in the interior space and operable to emit a laser beam having a selectable wavelength. A focusing lens assembly is positioned in the interior space along an optical path of the laser beam to operatively couple the laser beam to the optical output interface.

Abstract: A method of forming a solar cell including: providing a semiconductor body including at least one photoactive junction; forming a semiconductor contact layer composed of GaAs deposited over the semiconductor body; and depositing a metal contact layer including a germanium layer and a palladium layer over the semiconductor contact layer so that the specific contact resistance is less than 5×10?4 ohms-cm2.

Abstract: Methods of attaching an optical line to a phase modulator in a fiber optic gyroscope. The methods include positioning at least one end of the optical line relative to a side of the phase modulator. The end of the optical line may have a first non-perpendicular angle and the side of the phase modulator may have a second non-perpendicular angle. The end of the optical line may be attached to the side of the phase modulator with the end of the optical line being non-parallel to the side of the phase modulator. The optical line may be an optical coil or a light path.

Abstract: A method and apparatus are provided for protecting a semiconductor device from damage. The method may include the steps of providing an active semiconductor device on a surface of a semiconductor substrate where the active device is surrounded by an inactive semiconductor area, and providing a soft metallic guard element in the inactive semiconductor area around at least a portion of the periphery of the active device wherein the metallic guard element is connected to ground potential and not to the active device.

Abstract: An apparatus for analyzing, identifying or imaging an target including first and second laser beams coupled to a pair of photoconductive switches to produce CW signals in one or more bands in a range of frequencies greater than 100 GHz focused on, and transmitted through or reflected from the target; and a detector for acquiring spectral information from signals received from the target and using a multi-spectral heterodyne process to generate an electrical signal representative of some characteristics of the target. The lasers are tuned to different frequencies and a phase modulator in the path of one laser beam allows the constructive or destructive interference of the signals on the detector as the laser beams are swept in frequency to be adjusted to achieve greater resolution in one or more selected frequency bands.

Abstract: A III-V compound semiconductor structure comprises epitaxial structures that include an integrated pair of different types of active devices. The semiconductor structure includes a semi-insulating substrate of a compound semiconductor III-V material and a first compound semiconductor III-V epitaxial structure disposed on the substrate. A concentration profile of dopant material in the semiconductor structure decreases substantially smoothly across an interface between the substrate and the first epitaxial structure in a direction from the first epitaxial structure toward the substrate, and continues to decrease substantially smoothly from the interface with increasing depth into the substrate despite the presence of silicon or oxygen contaminant at the interface. The interface is substantially free of a second contaminant that was present, during formation of the first epitaxial structure, in a chamber in which the first epitaxial structure was formed.

Abstract: An optical transmitter for generating a modulated optical signal for transmission over a fiber optic link to a remote receiver including a laser; an input coupled to the laser for directly amplitude modulating the laser with an analog RF signal to produce an output optical signal including an amplitude modulated information-containing component; and a phase modulator coupled to the output of the laser for reducing the distortion present in the received optical signal at the remote receiver.