Abstract: A broadband wavelength-division multiplexer comprises two input waveguides for two input signals, each of which is from a different wavelength band, a multi-mode interference waveguide for producing an output wavelength-division multiplexed (WDM) signal comprising the two input signals where at least one of the two input signals is partially coupled to produce the output WDM signal, and an output waveguide for providing the output WDM signal. Optionally, at least another output waveguide can be used to trap all or some power not coupled to produce the output WDM signal.

Abstract: A network system receives incoming packets from multiple private networks with potentially conflicting Internet Protocol (IP) address spaces, and performs header and payload address translation operations to ensure that the IP address spaces of the incoming packets are made non-conflicting, such that the packets can be managed using a single network management platform. A router in the system receives the packets and performs Network Address Translation (NAT) on IP header information. Packets identified as being associated with a particular protocol, e.g., a Simple Network Management Protocol (SNMP), are redirected by the router to a Management Payload Address Translator (MPAT) that applies a fast parsing process to the packet payloads to identify IP address-related information therein, and if necessary applies an appropriate translation of the identified information before routing the packets to a network management platform.

Abstract: Crosstalk and signal to noise degradation contributed by fiber nonlinearities in a WDM system are reduced by transporting data in a parallel format using a plurality of optical channels in a WDM signal as a parallel bus and by coding the parallel-formatted data so that bit patterns in the parallel-formatted information that would otherwise contribute to nonlinear impairments are changed. In one illustrative embodiment, an n-bit wide byte is transmitted using n optical channels (i.e., using n wavelengths) so that each of the n optical channels carries one of the n bits of the byte. In conjunction with the parallel transmission of information, a coding scheme is employed to reduce the occurrence of bit patterns, e.g., “all ones”, in the n-bit wide bytes that would give rise to four wave mixing or other nonlinear effects. The coding scheme may be used to transform bytes having “all ones” bit patterns to bytes having “non-all ones” bit patterns.

Abstract: A resonator for rf frequencies, especially microwave, in telecommunications systems, with an extremely stable resonant frequency over a desired operating temperature range, of predetermined width (Y) and thickness (X) and having a predetermined length (Z) in the direction of propagation for achieving a desired resonance, comprises a dielectric substrate of rutile, and first and second temperature compensating layers of sapphire on two opposite faces of the substrate and extending along the length of the substrate, these sapphire layers having a predetermined thickness, and first and second superconducting layers formed on the outer surfaces of the temperature compensating layers.

Abstract: The present invention concerns the efficient use of the radio spectrum in wireless communications. Channel occupancy data and channel availability data concerning a specific base station and its neighbors are used to assign frequency channels to mobile units and/or base stations. The channel occupancy and availability data may be located at a base station or at a mobile switching center. Channels are preferably assigned as channel pairs.

Abstract: In a wireless transmission system that transmits the same information in parallel using two or more different types of modulation schemes, such as a satellite-based digital audio transmission system transmitting two TDM signals and a single OFDM signal, a receiver processes the differently modulated signals to generate separate demodulated signals that are then combined to form a single combined signal for further processing (e.g., decoding). In one embodiment, the receiver applies a maximal ratio combining (MRC) technique to generate a single optimal ratio combined signal from the differently modulated signals. By combining the differently modulated signals using an MRC technique, the adverse affects of noise related to inter-symbol interference in the individual signals can be reduced and the complexity of hardware in the receiver can be reduced.

Abstract: An optical transmission system exploits the reduced signal-to-noise (SNR) requirements for low-bit rate channels to devise a new wavelength channel allocation scheme which increases the number of channels that a WDM system can support. Wavelengths of low-bit rate channels are assigned outside a flat-gain window (i.e., flat-passband region) of the system. The channel allocation scheme uses the high-bit rate channels located in the flat-passband region of wavelengths and the lower-bit rate channels located outside this passband region with progressively lower-bit rate channels located farther outside this passband region. Low-bit rate channels are also assigned to region(s) of the passband where the non-linear threshold power level of the system may be exceeded.

Abstract: An echo canceling system with self deactivation includes an echo canceller based on an adaptive filter, and an echo detector. The adaptive filter determines an estimate of an echo signal present in an untreated signal received from a “near” end of a communications channel. In order to produce an echo-canceled received signal, the echo canceller subtracts the estimated echo from the untreated received signal. The echo detector compares the energy of the untreated received signal and the energy of the echo-canceled received signal. The difference represents the energy in the estimated echo signal generated by the adaptive filter. If this energy is large, significant echo is present. The echo canceller remains activated, and the echo detector selects the echo-canceled received signal for output. If the estimated echo energy is small, little or no cancelable echo is present. The echo canceller is deactivated, and the echo detector selects the untreated received signal for output.

Abstract: A method for encoding handwritten symbols operates upon penstroke data received from a device capable of sampling a stylus position at discrete intervals. Each handwritten symbol is segmented into an ordered sequence of discrete strokes. An are length and initial and final tangent angles are evaluated for each of these strokes. Each stroke is encoded in the form of a parameter set comprising position coordinates of the initial and final endpoints of the stroke, the arc length, and the initial and final tangent angles. In specific embodiments of the invention, the segmentation is based, in part, on properties of the handwritten symbol when it is expressed as a curve &phgr;(s), wherein s represents arc length and &phgr; represents the net turning angle.

Abstract: Voice mail, email, fax and personal calendar systems are integrated allowing for the automatic updating of voice mail and email responses to received telephone calls and emails indicating that the receiver of the telephone call/email is out of the office, temporarily unavailable, etc. For received telephone calls, a determination is made as to whether the call was received during or outside of normal working hours, and if the person receiving the call is still engaged beyond a previous entered time period for providing an appropriate message to the caller. The determination is also made as to whether the received call is an “inside” or “outside” call, e.g., originating within or outside of the office or organization being called, and a predetermined response is provided depending upon where the call originated.

Abstract: A polarized organic photonics device, including an LED or photovoltaic device, is comprised of a first conductive layer or electrode coated with a friction transferred alignment material, a photoactive material, and a second electrically conductive layer or electrode. The alignment material provides for the orientation of the subsequently deposited photoactive material such that the photoactive material interacts with or emits light preferentially along a selected polarization axis. Additional layers and sublayers optimize and tune the optical and electronic responses of the device.

Abstract: A fiber optic splice holder with a slack storage feature has a reel having a hub for fiber slack storage, and a means for holding a splice at its center, whereby fiber slack can be stored and retrieved while protecting the fiber splice, in a manner which avoids entanglement with other splices and fibers. The reel is supported by a reel holder, which can be reversibly mounted in a modular rack for easy storage, and permits easy access to individual splices and accompanying slack.

Abstract: A channel selector which selects one or more channels from input multi-channel optical signals for routing to predetermined destinations within an optical communication system is disclosed. The channel selector selects one or more channels by first splitting portions of the input multi-channel optical signals across two or more optical paths. Thereafter, a desired phase response is applied to the split portions of the multi-channel optical signals. The desired phase response is applied to the split portions of the multi-channel optical signals so the channels therein interfere with each other either constructively or destructively when the split portions of the multi-channel optical signals are combined. The channel selector has a structure which includes a plurality of input ports, a plurality of output ports, a splitter, a combiner, one or more all-pass optical filters, and a plurality of optical paths.

Abstract: The present invention generally relates to the field of optical transmission and particularly to a method and an apparatus for controlling the optical power of an optical transmission signal in a wavelength division multiplex optical transmission system (WDM system). The optical power of a control channel is controlled to keep the total optical power of the optical transmission signal constant. The present invention avoids the deleterious effects of stimulated Brillouin Scattering by spreading the power density spectrum of the optical control signal.

Abstract: An optical add-drop module (OADM) includes in the through-path exactly two thin-film filters (TFFs) having respective passbands that approximately coincide in wavelength. Each TFF has a respective across-the-band isolation level, representing the smallest isolation achieved at any wavelength within the passband. The respective reflection characteristic curves of the two TFFs are at least partially complementary, such that the OADM isolation level exceeds the logarithmic sum of the across-the-band isolation levels of the respective TFFs.

Abstract: A stack of two or more birefringent crystals having complimentary properties is arranged to have zero net beam walk-off at off-normal incidence and a finite free-spectral range. In another embodiment, the birefringent crystal materials are selected to provide reduced temperature dependence. The result is an optically and mechanically stable composite birefringent crystal unit. A variety of folded birefringent filters are implemented using the composite birefringent crystal.

Abstract: An optical device for full duplex free space light transmission comprises a transmitting light source, having a transmitting optical axis and a radiated beam, and a receiving light detector having a receiving optical axis and a field of view. The transmitting optical axis and the receiving optical axis are nonparallel and substantially in the same plane.

Abstract: Transmission-based data security is provided in dense wavelength division multiplexing systems using a transmission scheme that incorporates hierarchical scrambling techniques with a unique multiplexing arrangement. Information supplied by one or more sources is multiplexed according to a predetermined scrambling pattern and transmitted in a parallel format using one or more wavelength channels in a wavelength division multiplexed signal. By transmitting the multiplexed and scrambled information in parallel, the wavelength channels effectively function as a parallel bus (a “wavelength bus”). Multiple stages of scrambling can be applied to the multiplexed and scrambled information transported in the wavelength bus. For example, individual bit streams carried within each wavelength channel of the wavelength bus can be separately scrambled according to another predetermined scrambling pattern.

Abstract: A step-index fiber bundle utilized in communicating optical Gigabit Ethernet signals from multiple Gigabit Ethernet optical transceiver interfaces directly to an array of Gigabit Ethernet receivers and lasers integrated on an optoelectronic-VLSI chip, with the step-index fibers in the bundle having core sizes between 50 um and 60 um to facilitate the fabrication of the bundles. The step-index fiber is selected to exhibit a numerical aperture between 0.19 and 0.25 to cooperate with a standard Gigabit Ethernet 50 um graded-index fiber jumper between each individual transmitter interface and the fiber bundle, and with a standard Gigabit Ethernet 62.

Abstract: An electronic odor sensor includes first and second amplifiers, a biasing network, and a device connected to receive the output signals from the first and second amplifiers. The device is configured to correlate the received output signals to the presence or absence of an odor. The first and second amplifiers have respective first and second organic semiconductor layers and are configured to produce output signals responsive to the conductivities of their respective organic semiconductor layers. The conductivities of the organic semiconductor layers are responsive to voltages applied to associated ones of the amplifiers and to the presence of the odor. The biasing network applies the voltages to the amplifiers.