Abstract: A laser processing fixture is formed to allow for facet processing of cleaved laser bars, either individually, or allowing for multiple bars to be processed simultaneously. The fixture holds the bars at a precisely-controlled distance with respect to a predefined reference plane, and holds the bars rigidly enough so as to minimize the possibility of vibration, but not so forcefully as to cause damage. The fixture comprises a fixed jaw and a movable jaw, with a pair of spaced-apart support members extending between the jaws. One or more laser bars may then be positioned between the jaws such that the front and rear facets will be exposed above and below the jaws. Therefore, each facet may be processed without unloading and re-loading the bars in the fixture. The support members, which may comprise a pair of wires, are spaced a sufficient distance so as to be disposed beyond the location of any active device region.

Abstract: A fiber Raman amplifier with increased gain and improved pump conversion efficiency is formed by including a high pass optical filter in the amplifier structure. The filter may comprise one or more discrete components, or may be formed as a “distributed” filter along the length of the fiber amplifier. The cut-off frequency for the high pass optical filter is selected to be immediately below the frequency of the input signal to be amplified. When used in an arrangement with multiple input signals, the cutoff frequency is controlled to be immediately below the lowest input signal frequency.

Abstract: A fiber Raman amplifier is configured to use a co-propagating Raman pump source, which may be beneficial in a variety of system configurations (for example, in bidirectional communication systems). By carefully configuring the pump source characteristics, sufficient optical gain can be achieved in the co-propagating arrangement, the characteristics including: (1) using an optical pump power of at least 50 mW, (2) having a relatively large spectral bandwidth within the pump (to suppress SBS); and (3) a frequency difference between all longitudinal pump modes of each pump laser being separated by at least the walk-off frequency between the pump laser frequency and the signal frequency, and all intense longitudinal modes between different pump lasers being separated by at least the electrical bandwidth of the communication system.

Abstract: A vacuum-assisted arrangement for testing integrated circuits uses a first vacuum source to removably hold a test socket in place with respect to a test fixture. The socket further includes a plurality of alignment features to allow for the socket to be self-aligned with respect to the fixture. A second vacuum source is coupled through the combination of the fixture and the socket and is used to hold a device-under-test in place within the socket. The socket is formed to including a plurality of conductive elastomer contacts and the application of a consistent vacuum force allows for consistent testing of the integrated circuit devices.

Abstract: A measurement tool for assessing the wavelength linearity of an optical spectrum analyzer utilizes the linear skirt slope region of the included resolution bandwidth filter. The input wavelength is swept from a predetermined start value to a predetermined stop value, and the associated amplitude is recorded. The insertion loss associated with the system is first determined so that this loss can be removed from the recorded amplitude values. By knowing the skirt slope and the measured amplitudes, the wavelength offset can be determined.

Abstract: A polarization mode dispersion (PMD) measuring arrangement utilizes a tapped-off portion of a signal that has experienced dispersion (such as, for example, propagating through a dispersive optical fiber). The measuring arrangement utilizes a phase-sensitive single sideband detection circuit in conjunction with a polarization beam splitter to generate magnitude and phase information for the lower and upper sidebands of each polarization of the received signal. The magnitude and phase information collected at a single frequency can be used to determine the polarization mode dispersion, eliminating the need to sweep the center frequency of the received optical signal to generate the PMD measurement.

Abstract: A variable fiber optic attenuator is formed of a first, movable section of optical fiber and a second, fixed section of optical fiber. The fibers are disposed end-to-end on a substrate, where the substrate includes a cavity formed underneath an end portion of the movable fiber. As supported, the fiber endfaces are aligned such that complete optical coupling is achieved between the fibers. Upon application of an external force to the first, movable fiber, the end portion of the fiber is forced downward into the cavity (such as, for example, by application of an external magnetic field and the inclusion of a permalloy sleeve around the end portion). As the fiber moves downward into the cavity, the endface will become misaligned with the endface of the fixed fiber, leading to attenuation of the signal passing through the fixed fiber. By controlling the force applied to the movable fiber, the degree of attenuation can be well-controlled.

Abstract: A stabilized single-longitudinal-mode laser where stabilization is performed through a pair of Bragg reflector mirrors slightly displaced in wavelength to either side of the longitudinal mode selected for operation. Transmitted signals through each Bragg reflector are detected and used in an electrical servo loop to control the relative positions of the longitudinal mode selected for operation and the peak wavelengths of the two Bragg reflector mirrors.

Abstract: Silica sols exhibiting desirable yield-dilatancy are fabricated. A mixture comprising silica, water, and a pH-adjusting agent is provided, and the mixture is shear-mixed. The desirable properties of the resultant sol are attained by using a concentration of pH-adjusting agent that provides a viscosity within a particular range during shear mixing. The requisite pH range, however, changes depending on the properties of the silica mixture. A discovered technique for determining this changing pH range is by selecting the pH based on the silica surface area per unit volume of the mixture.

Abstract: A self-aligned 1×N fiber optic switch uses silicon optical bench technology to provide the alignment between the single fiber and the “selected” one-out-of-N fibers. A first substrate stack is used to support the single fiber, using a via etched through the thickness of the stack, and includes alignment fiducials formed on the top surface thereof. A second substrate stack is used to similarly support an array of N fibers, the array disposed in a circular arrangement with respect to the top surface of the second substrate stack. A set of alignment fiducials is also formed on the top surface of the second substrate stack. One alignment feature includes a “centering” fiducial to allow for the two stacks to be properly aligned. Another alignment fiducial includes a circular channel, having a diameter greater than that of a fiber array, and allowing for alignment sphere to “rest” in the channel when the substrate stacks are mated.

Abstract: A precision grating period measurement system uses a pair of properly positioned photodetectors to provide sub-Angstrom resolution. That is, the absolute position of a first detector with respect to a zero point in the measurement system is assured by including a second photodetector that measures a retroreflected signal. The system is then “zeroed” on the retroreflected signal such that the subsequent measurements recorded by the first photodetector are a precise measurement of the grating period.

Abstract: An automated monitoring and notification system for use with a testing arrangement is able to identify “potentially faulty test sockets”. The system uses a set of pre-existing data contained in a manufacturing database regarding the number of device failures for each socket. A threshold number of consecutive device failures is used to flag a particular test socket as “suspect”. Another database, containing historical “failure” data for the test sockets is then queried upon identification of each “suspect”. When the number of “failures” for a “suspect” exceeds a predetermined threshold, the socket is identified as “potentially faulty” and an alarm is sent to the system user.

Abstract: A screen assembly for use in a rear window of a vehicle such as a pick-up truck is formed of a laminate structure including a screen element disposed between a pair of plastic frame members. The structure is glued together to permanently fix the screen between the pair of frames, forming a structure with sufficient strength to withstand the air circulation between a truck bed and cab when a rear window is opened. A screen window track is attached to the exterior of the existing rear window using a double-sided adhesive. In some cases, the screen track may be attached directly to the window using double-sided tape (i.e., attached to the right hand and left hand sides) if the periphery or surface area of the window border is too narrow to support the screen frame.

Abstract: An automated “tuning” system is disclosed that utilizes the known tuning curve (on an approximation thereof) to control the tuning process. In particular, the tuning curve is transformed (if necessary) into a quadratic with a local maximum, where the maximum is associated with the optimum tuning value. In one embodiment, the tuning system of the present invention may be used to provide alignment between optical components. The system may be organized to recognize “backlash” in the tuning process and perform additional tuning adjustments to overcome this backlash. Each tuning curve may be one-dimensional and a set of such curves used to provide for an N-dimensional tuning.

Abstract: A Michelson interferometer optical mirror switch is formed to include an optical signal path adjustment arrangement to transform the switch between a first, “pass through” state and a second, “reflective” state. A pair of input optical signal paths are coupled into an optical beam splitter that thereafter directs 50% of each optical signal toward a mirror element. The reflected signals then pass back through the beam splitter. If the optical path lengths are equal, an optical signal entering a first signal port will be coupled into a second signal port (the “pass through” state). If the optical path lengths differ by an odd, half-wavelength amount, the reflected signals will be directed back into the optical signal port of origin (the “reflective” state).

Abstract: A method of forming selected Group III-nitride regions uses a masking layer to cause differential growth between single crystal Group III-nitride material and polycrystalline Group III-nitride material. The epitaxial process is chosen to provide vertical growth so as to allow for replication of the mask edges at the defined limits for the selected regions. By using an etchant that is selective between polycrystalline and single crystal Group III-nitride material, the polycrystalline material (that grew over the mask layer) can be removed, leaving only the single crystal Group III-nitride (that grew over the exposed substrate material).

Abstract: A user-programmable bass/treble control circuit is embedded within a conventional remotely located codec. A subscriber station set is capable of transmitting out-of-voiceband “control” tones to increase/decrease bass and treble. A tone detector within the codec recognizes and removes these control tones, forwarding them to a programmable equalization filter inserted in the transmit signal path in the codec. The equalization filter will adjust the bass and treble of the to-be-transmitted signal in accordance with these received control tones. Advantageously, the “listener” at the other end will not hear the tones if the tone detector is inserted before the receiver. The user may adjust the tones during the entire conversation and the filter may be “reset” at call completion.

Abstract: An improved anvil tool for use in laser bar or wafer cleaving comprises a relatively small cross section such that the anvil does not overhang the device edges in any direction. In one embodiment, the surface of the tool contacting the laser wafer or bar is compliant and contains a laterally disposed slit that aligns with the scribe mark on the top surface of the material to be cleaved. The anvil may be formed as a columnar tool or as a film deposited on a substrate. The compliant surface may be removable and in a preferred embodiment may comprise a continuous feed membrane tape so that a “clean” surface is used for each subsequent cleave operation.

Abstract: An arrangement for providing attachment and alignment between an array of surface emitting lasers and an array of optical fibers utilizes a first substrate for supporting the laser array and a second substrate for supporting the fibers. The second substrate is formed to including a plurality of apertures that are disposed to self-align with the laser array upon attachment. Alignment fiducials may be formed on both substrates to facilitate the alignment.

Abstract: An optical power monitoring tap for use in an optical transmission system advantageously uses existing reflected signal(s) within the transmission system as the “tap” source for the monitor. In particular, one or more multimode fibers are disposed so as to capture reflected signals and directed the reflections into a optical power monitor, such as a PIN photodiode. One or more interfaces within the transmission system (such as a face of an included GRIN lens) provides the reflected signal. In one embodiment, a set of three multimode fibers may be used to capture reflected signals from both an included GRIN lens and isolator component.