Abstract: A method of fabricating an integrated circuit on a compound semiconductor III-V wafer including at least two different types of active devices by providing a substrate; growing a first epitaxial structure on the substrate; growing a second epitaxial structure on the first epitaxial structure; and processing the epitaxial structures to form different types of active devices, such as HBTs and FETs.

Abstract: An optical communication system for generating and transmitting a modulated optical signal in which light emitted by a light source is modulated by an optical modulator in accordance with an input electrical signal. A bias signal generator applies a bias electrical signal to bias the optical modulator at a bias angle away from quadrature. The bias signal generator monitors the input electrical signal and adjusts the applied bias electrical signal in dependence on the input electrical signal. The system further includes a receiver which may include an equalizer coupled to the photodetector of the receiver.

Abstract: An optical assembly includes a light path and at least one optic to be positioned in the path. A support arrangement supports the optic having a foot arrangement including at least one foot that receives a direct manipulation with the foot slidingly engaged against a support surface to move the optic relative to the light path. Movement of the foot may move the optic along a predetermined path. The foot defines a footprint for engaging the support surface and receives the direct manipulation in a way which changes the footprint on the support surface to move the optic responsive to changes in the footprint. A movement arrangement may selectively bias the foot against the support surface during a movement mode, intended to permit movement of the foot against the support surface, and in a locked mode, intended to lock the foot against the support surface.

Abstract: A method comprising generating an optical beam with a laser, filtering the optical beam to select a desired wavelength with an etalon positioned in a path of the optical beam, heating the etalon to an operational temperature using a heater, monitoring the operational temperature of the etalon with a resistive thermal device disposed in or on a thermally conductive frame bonded to the etalon, and applying feedback control of the heater based on the monitoring to select the desired wavelength.

Abstract: A GPON module comprises a housing and a circuit board disposed in the housing. The circuit board further includes ground lines that substantially isolate regions of the circuit board, an electro-optical interface for converting an inbound optical signal to an electrical signal and processing circuitry that is arranged to provide an electrical RF signal to an RF interface. The RF interface comprises a three-pin RF connector exposed from the housing, wherein the RF connector is coupled directly to the circuit board, and two of the three pins are coupled to ground.

Abstract: A coherent light source having a semiconductor laser resonator and an optical amplifier which amplifies coherent light emitted by the semiconductor laser resonator in response to current injection, in which the amount of current injected into the semiconductor laser is controlled for conformity with a chirp requirement of an optical communication system. The optical amplifier, which introduces no chirp, may be controlled to match an optical power requirement of the optical communication system. A heater may be provided to introduce a low frequency chirp in order to suppress interferometric intensity noise and unwanted second-order effects such as stimulated Brillouin Scattering. The optical amplifier may be monolithically formed with the semiconductor laser resonator, with separate electrodes provided for injecting current into the semiconductor laser resonator and the optical amplifier.

Abstract: A method of fabricating an integrated circuit on a compound semiconductor III-V wafer including at least two different types of active devices by providing a substrate; growing a first epitaxial structure on the substrate; growing a second epitaxial structure on the first epitaxial structure; and processing the epitaxial structures to form different types of active devices, such as HBTs and FETs.

Abstract: Disclosed herein are methods of detecting organic materials, and more particularly, methods of detecting organic materials using terahertz spectroscopy. The method of detecting organic material using terahertz spectroscopy includes suspending organic material in a medium to form a sample; irradiating the sample with an illumination beam of electromagnetic radiation, the illumination beam having a plurality of frequencies in the range of about 100 GHz to about 2 THz; detecting radiation transmitted through and/or reflected from the sample; and, analyzing the detected radiation to identify the organic material, wherein the medium is selected from the group consisting of agar, guar gum, gellan gum, carrageenan, xantham gum, fibrous sodium pectate, and other agar substitutes.

Abstract: Techniques are provided for implementing a burst mode optical receiver capable of maintaining a stable gain profile in response to a burst signal. The optical receiver has a photodiode in balanced circuit configuration with a separate RF amplifier stage connected to each terminal of the photodiode. The two RF amplifier stages are coupled to biasing voltage sources that are inverted in comparison to the terminal connections and that, in some examples, each contain a field effect transistor (FET) that having a gate that is controlled in response to a sensed voltage. The burst mode optical receiver may be used in numerous applications, including optical line terminations (OLTs) in passive optical networks (PONs).

Abstract: An optoelectronic module for converting and coupling an information-containing electrical signal with an optical fiber including a housing having an electrical input for coupling with an external electrical cable or information system device and for transmitting and receiving information-containing electrical signals over such input, and a fiber optic connector adapted for coupling with an external optical fiber for transmitting and receiving an optical signal; an electro-optic subassembly coupled to the information containing electrical signal and converting it to and/or from a modulated optical signal corresponding to the electrical signal; and parametric storage means disposed in said housing for storing environmental and/or operational data associated with the module, and an optional method for time-biased lossy compression of such stored data.

Abstract: A vertical surface emitting laser having a mesa structure formed with sloping side walls. A passivation layer including at least two sublayers at least partially covers the mesa structure. The at least two sublayers have differing stress components arranged to at least partially counter each other. By making the mesa structure with sloping side walls, the deposition of the passivation layer in such a way as to minimize the net stress of the passivation layer is facilitated. In addition, the mesa structure has a first stack of mirror layers comprising a semiconductor material doped with a first dopant and having first peripheral oxidized portions extending a first distance into said first stack, and a second stack of mirror layers comprising a semiconductor material doped with a second dopant and having second peripheral oxidized portions extending a second distance into said second stack, wherein the first distance is different from the second distance.

Abstract: An adapted semiconductor laser package that may convert a first type of package pin-out arrangement to a desired pin-out arrangement. The laser package may include a laser package including a laser, an isolator, a lens, a fiber sleeve, and a pin-out arrangement. The isolator and the fiber sleeve may be jointly arranged away from the laser. The laser package may also include an adapter with a first section with a plurality of holes geometrically arranged and mated with the package pin-out arrangement, a second section with an adapter pin-out arrangement with two rows of pins extending along opposite sides of the package, and electrical connections between the plurality of holes and the pins.

Abstract: A passive optical network transceiver includes an avalanche photodiode, a bias voltage generator for supplying a bias voltage to the avalanche photodiode, a temperature detector for measuring the operating temperature of the avalanche photodiode, a memory for storing one reference bias voltage and a processing circuitry to process the value of the measured operating temperature and the reference bias voltage to generate a control signal for controlling the bias voltage generator to adjust the bias voltage supplied by the said bias voltage generator.

Abstract: Briefly, in accordance with one or more embodiments, a thermally controlled optical filter comprises a frame coupled to an etalon where the frame includes a resistive thermal device disposed on the frame to obtain thermal measurements of the etalon during operation. The frame may be generally L-shaped or generally square-shaped. The frame may include a fillet that is generally planar, generally beveled or trapezoidal, or generally circular in shape. A heater may be additionally disposed on the frame. The etalon and frame subassembly may be bonded to a micro hot plate that is capable of heating the etalon to an operational temperature.

Abstract: A circuit controlling the gain of an amplifier in an optical transmitter used for optical communication, including a detection circuit for measuring the power of the RF input to a laser; a gain controller or controlling a gain of an amplifier, and a switch connected to the gain controller, wherein the gain controller is adapted, in response to an activation of a switch, to: (i) automatically vary gain of the amplifier, and (ii) set the gain of the amplifier at a level corresponding to a reduction in the noise and/or distortion associated with the transmitter.

Abstract: An optical fiber communications apparatus comprises a housing provided with a motherboard and a plurality of modular cards , each of which is engageable with the motherboard via one of the card receptors. A optical card includes an optical transceiver for communication using a digital, optical communications signal over a single optical fiber link. Each modular card is provided with a plurality of circuit sub-assemblies, each circuit sub-assembly being configured for digital communication with a respective local audio, video or data electronic device via a respective connector using a respective electronic information-carrying signal. Each circuit sub-assembly is configured for communication of an audio, video or data information-carrying signal with the transceiver using the digital, optical communications signal.

Abstract: A fiber-optic transmission system includes a transmitter having a designed chirp value. The transmitter has first and second inputs for receiving first and second input signals, respectively, used to produce a modulated output signal. An optical fiber is responsive to the transmitter for receiving the output signal. A circuit asymmetrically drives the first and second input signals so as to change the designed chirp value of the transmitter to another value. Methods of controlling the chirp of a commercially available transmitters are also disclosed. Because of the rules governing abstracts, this abstract should not be used to construe the claims.

Abstract: An optical transmitter for generating a modulated optical signal for transmission over a fiber optic link to a remote receiver including a laser; a modulator for externally modulating the optical output signal with a RF signal to produce an optical signal including a modulated information-containing component; and a phase modulator coupled either to the output of the modulator or directly to the output of the laser for reducing or canceling the noise signals generated in the laser.

Abstract: A PIN photodiode having a substrate, a first type electrode layer disposed on the substrate, a first layer of intrinsic material disposed over a portion of the first-type electrode layer, and a first type window layer disposed over the intrinsic layer. An island shaped region of intrinsic material is disposed over the window layer and a dielectric layer is disposed over the island region and at least the peripheral portion of said island shaped region whereby an opening is formed in the island shaped region. A dopant is diffused through the opening so as to form a PN junction that extends into the first layer of intrinsic material.