Abstract: Temperature compensation of a wavelength-division-multiplexed (WDM) passive optical network (PON) communication system uses power measurements from each of it remote nodes (RNs) to adjust the frequency of an associated multifrequency laser (MFL). Changes in the power level at each RN caused by frequency drift of its waveguide grating router (WGR), due to changes in the WGR temperature, is determined by monitoring the power level received at each RN and corrected by appropriate changes in the temperature of the associated MFL. The WGR uses one output port (e.g., channel 1) which is looped-back through the WGR a second time to increase the temperature sensitivity of the power measurements. A temperature-control algorithm controls the temperature of the MFL as a function of changes in the received power at the WGR.

Abstract: Embodiments of the invention include an optical energy transmission system, method and apparatus having improved mode coupling. According to embodiments of the invention, an optical energy transmission medium such as an optical fiber includes a plurality of particles formed in one or more coating region layers surrounding the cladding region and/or one or more buffer region layers surrounding the coating region for inducing microbending thereof, thus promoting advantageous mode coupling, which improves bandwidth potential by reducing dispersion. The method for manufacturing the inventive optical energy transmission medium includes forming one or more coating region layers and/or one or more buffer region layers containing particles such as fumed silica in such a way that particles are maintained within the optical energy transmission medium and form controlled perturbations along the optical fiber that enhance mode coupling to the extent that bandwidth of the optical fiber is improved.

Abstract: A method and system for reducing the effects of atmospheric ducting on wireless transmissions, wherein a wireless communication system is comprised of a plurality of base stations having antennas, each base station having a beacon signal transmitter and a beacon signal receiver. Each beacon signal transmitter is configured to transmit a wireless beacon signal to be received by the beacon signal receiver at other, preferably every other, base stations. For each wireless beacon signal, a time delay and a propagation loss is measured. Each measured time delay and propagation loss is compared to an expected time delay and an expected propagation loss corresponding to the wireless beacon signal. The results of the comparison are processed so as to determine a location of atmospheric ducts in the region serviced by the wireless system.

Abstract: In accordance with the invention, an optical fiber is provided with a metal coating of controlled variable thickness by the steps of disposing the fiber in position for receiving coating metal from a metal source, and depositing metal while moving a shadow mask between the fiber and the source to provide patterning of deposited metal. Advantageously, the mask is translated at a constant velocity perpendicular to the fiber. The method is particularly useful for the fabrication of adjustable Bragg gratings.

Abstract: A method for manufacturing an integrated circuit structure is provided having a semiconductor substrate and depositing a layer to be patterned on the semiconductor substrate. An organic anti-reflection coating is deposited on the layer to be patterned and then an organic photoresist on the anti-reflection coating. The photoresist is patterned and developed to form an opening having side walls and to expose a portion of the anti-reflection coating. The photoresist and the exposed portion of the anti-reflection coating adsorb non-active molecules. A unidirectional electron-ion bombardment causes desorption of non-active molecules that gives access of active molecules to the exposed surface of the anti-reflection coating. Bombardment also causes decomposition of non-active molecules on the exposed surfaces, which produces active atoms. Both processes provide unidirectional removal of the anti-reflection coating without attacking the photoresist side walls and underlying layers.

Abstract: In accordance with the invention, a WDM optical system comprises a transmission line with a net negative dispersion rather than the conventional net positive dispersion and a DCG with a positive dispersion rather than negative dispersion. With this design, short wavelengths entering the grating are reflected first before the long wavelengths, minimizing the path of short wavelengths within the grating and thereby avoiding short wavelength cladding loss. In advantageous embodiments, the DCG compensates for both the net negative dispersion and dispersion slope of at least two signal channels and preferably of all signal channels.

Abstract: A method and assembly for optically connecting a first grouping of optical fibers with a second grouping of optical fibers. To form the optical connection, the optical fibers in the first grouping and the second grouping are set into two separate arrays. A plurality of collimating elements are positioned proximate both arrays. The collimating elements correspond in both number and orientation to the optical fibers. As a result, any light signal emanating from either the first array or the second array will pass through a collimating element and will become substantially collimated. The first array and the second array are oriented with respect to one another so that each collimated element is at least partially aligned with a collimating element from the opposing array. Accordingly, light emitted from one fiber element in one array will be focused on an optical element in the opposing array without the optical fibers being precisely aligned.

Abstract: A tunable integrator circuit having a main amplifier with an input resistor R and a feedback capacitor C and a tuning amplifier having a variable gain k between the output of the main amplifier and the feedback capacitor. The circuit has an effective capacitance of kC. Thus the integrator can be tuned to compensate for temperature and processing variations of the RC product by adjusting the gain of the tuning amplifier. The tuning amplifier can also be used to multiply the effective capacitance of the filter, kC, by increasing the gain k of the tuning amplifier beyond that needed to compensate for RC variations, thus reducing the area required for on-chip capacitances while maintaining a constant resistance. The circuit can be used independently or in conjunction with a capacitor array.

Abstract: A technique for generating and displaying views of hierarchically clustered data in a computer system. A binary tree is stored in memory of a computer system. The leaf nodes represent data items and the interior nodes represent clusters of the data items and a measure of dissimilarity between child clusters. The nodes of the tree are traversed and a display area is recursively split until nodes having a certain level of dissimilarity are reached, at which time a group rectangle is drawn around the current rectangle. Lower level nodes continue to be processed so that all data items are displayed in the display area. During the splitting of rectangles, the rectangles are split along the longest axis to produce better dimensioned rectangles. Upon generating a new display at a different level of dissimilarity, all data items are displayed in their same relative location, with only the resulting groups changing.

Abstract: An antenna array system includes a first array for operating in a transmit mode and a receive mode and a second array spaced apart for operating in the receive mode. A receiver adjusts a receive radiation pattern in the receive mode and provides a control signal for a transmit radiation pattern of the transmit mode.

Abstract: The present invention discloses a method for transmitting messages to components in a wireless communication system using a server process. In an embodiment of the present invention, the wireless communication system is a set of interconnected nodes with a main circuit board connected to zero or more components. To transmit a message to a component in the wireless communication system, the message is first encapsulated with a reference label that is associated with a component to which the message is to be sent, i.e., destination component. Upon encapsulation, the message is then transmitted to a destination node, which is a node on which resides the destination component. At the destination node, a server process determines an address for the destination component using the reference label.

Abstract: A system and method are described for modulating phase and polarization aspects of an optical carrier signal with URZ and URZd coded representations of source data, where the source data itself is transmitted via an optical transmission system using UNRZ coding. At a receiver, the URZ and URZd signals are summed to provide a UNRZ equivalent encoding of the source data. That UNRZ-equivalent encoded signal is then combined with the received UNRZ signal to produce a composite UNRZ encoded representation of the transmitted source data. In carrying out the method of the invention, noise attributable to random fluctuations in phase and polarization of the optical carrier signal is reduced and the composite UNRZ coded signal obtained at the receiver provides a more reliable indicia of the encoded transmitted data.

Abstract: A headend of a shared data channel receives data packets, each data packet being addressed to a user of the shared data channel. A buffer of the headend queues the data packets, and a router of the headend assigns high transmittal priority to data packets addressed to users who have more recently received a previous data packet and assigns low transmittal priority to data packets addressed to users who have relatively less recently received a previous data packet, wherein the low transmittal priority is a lower priority than the high transmittal priority.

Abstract: A method for scheduling access of data blocks located in a computer system having a plurality of disk drives, each disk drive has a disk cache with a specified fence parameter value coupled to a host computer via a common bus. The method according to one embodiment, comprises the steps of: (a) sequentially accessing each of the disk drives for a predetermined number of iterations to retrieve a predetermined number of data blocks; (b) for a specified number of the iterations, transferring data located in the disk cache to be transferred to the common bus and requesting data corresponding to the following iteration to be transferred to the disk cache; and (c) repeating steps (a) and (b) until the predetermined iterations are completed.

Abstract: A method of thinning a cut electron transparent membrane used in transmission electron microscopy is disclosed. An electron transparent thin film membrane is cut from a sample that is positioned within a focused ion beam device by focusing an ion beam in a predetermined direction onto the sample to mill the sample and cut the transparent thin film membrane from the sample. The membrane is mounted onto a transmission electron microscope grid having a mesh surface and carbon coating. It is mounted in a vertical orientation onto a support stage of a focused ion beam device such that the membrane is mounted vertically and parallel with the incident focused ion beam produced by the focused ion beam device. The support stage is tilted a predetermined amount to orient the membrane at an angle incident to the focused ion beam. The ion beam is focused at a glancing angle into a predetermined portion of the membrane for thinning the membrane by cutting a thin portion from the membrane.

Abstract: An optical fiber grating device including a length of optical fiber having a predetermined fundamental mode effective guide index and a longitudinally tapered region for accessing a fundamental mode of light. The tapered region has a grating with a predetermined light spectral shaping property that shapes the light spectrum of the fundamental mode. A coating surrounds the tapered region of the fiber for modifying the fundamental mode effective guide index of the fiber in order to change the spectral shaping property of the grating.

Abstract: A device for determining at least a portion of a convex boundary of an object and a method of operating the same to determine the convex boundary or motion thereof. In one embodiment, the device includes: (1) first, second and third sensors, locatable about the object, that scan the object in corresponding first, second and third dimensions and produce signals indicating boundary sections in corresponding first, second and third planes and (2) a boundary integrator, coupled to the first, second and third sensors, that combines the signals to develop therefrom the convex boundary.

Abstract: A cap for protecting an electrical terminal from corrosion having a base which is insertable upon the terminal, a tapered section designed to guide and surround a mate to the terminal as it is being connected, and a removable top which protects the terminal before connection. The tapered section deforms during the connection operation to surround the mating terminal and seal the connection from corroding species.

Abstract: A simple, elementary switch fabric is provided for switching individual signals as a composite group based on group signal status that is embedded and carried within each of the individual signals in the group. In general, a group signal status is derived for a group based on the signal status of each of the individual signals within that group. This group signal status is then individually encoded and embedded in each of the individual signals in the group. The embedded group signal status can be extracted and decoded at any point within the transmission path, as necessary, to facilitate appropriate switching decisions. Although each individual signal is switched independently by the elementary switch fabric, the individual signals are effectively switched as a composite group because the switching decision for each individual signal in the group is based on the same group signal status.

Abstract: An arrangement and a method for monitoring and controlling an optical mechanical switch, which may include one or more microelectromechanical switches. In communication using the arrangement or the method, independently of any customer signal, a modulated optical signal is generated at wavelengths, both modulation and optical, that are out-of-band with respect the wavelengths of any transmission signals that may appear. The modulated optical signal is directed toward the optical mechanical switch, and system control parameters are changed to maximize a detected signal after passage through the optical mechanical switch. Any remnants of the modulated optical signal may be removed before arriving at any customer-related terminal. Optical cross-connect switching circuits are exemplary circuits in which the invention may be applied. The modulated optical signal is inserted before or during the transmission of any transmission signal.