Abstract: A stable single-mode wavelength selectable ring laser operates at a single wavelength which is selectable from any channel passband of a multiple-channel wavelength multiplex/demultiplexer element (e.g., an arrayed waveguide grating router (AWGR)). A Fabry-Perot semiconductor optical amplifier (FP-SOA) is connected together with the AWGR to form a ring laser structure where the FP-SOA is used as an intra-cavity narrow-band mode-selecting filter to stabilize ring laser oscillation to a single axial mode. This is the first time that a FP-SOA is used in a fiber ring laser as a mode-selecting interferometer with gain.

Abstract: A wavelength selective resonant grating exhibits transmission resonances when a single gap between two sections of a split gratings is used to provide a phase shift which is not a quarter wavelength in length or .pi./2 in phase. When the phase is changed to non - .pi./2 values (or the gap differs from a quarter wave), the transmission resonance moves from the center of the stop band. Appropriate adjustments of the phase over a .pi. interval allow tuning of the resonance across the entire stop band. The resonant optical wavelength grating can, illustratively, be used as wavelength filter, wavelength monitor, or as part of an Add/Drop arrangement.

Abstract: A variable dispersion optical unit is used to vary the relative dispersion between an input signal and an output signal of the optical unit under control of a control circuit. The control unit uses an optical homodyne detector to beat the input optical signal with the output optical signal to generate a control signal to adjust the relative dispersion a variable dispersive element. The variable dispersive optical element may be selected from a group of dispersive elements including at least a Bragg grating, a Fabry-Perot filter, a Mach-Zehnder filter, and a waveguide routing element. The variable dispersive optical unit can be used as part of a variable wavelength selective optical circuit (e.g., a tunable wavelength filter) where the varying dispersion characteristics is used to control the selection of the wavelength of the tunable wavelength filter, or is used to select the drop/add wavelength(s) of an Add/Drop circuit.

Abstract: An Add/Drop circuit for use in optical wavelength-division multiplexed systems includes fiber coupled four-port polarized beamsplitters and fiber Bragg grating filters.

Abstract: A wireless Local Area Network (LAN) includes a repeater which a) synchronizes interface adapters for portable end-user devices and b) retransmits data signals received which retimes and retransmits data signals received from these end-user devices that gain, one at a time, the exclusive right to transmit those signals during a given transmission time subframe by contending for access to the LAN resources that are auctioned off to permit LAN resource utilization that is independent of traffic load and that is implemented in a near collision-free environment.

Abstract: The self-phase modulation (SPM) effect in a dispersion compensating fiber (DCF) segment of an optical fiber transmission system is used to reduce the required length of the DCF segment needed to compensate the chromatic dispersion of a single mode fiber (SMF) segment of the system. It was determined that the length of the DCF segment at which the widest opening of the electrical eye diagram margin occurs, for a given optical input power to the DCF segment, decreases with increasing optical input power to the DCF segment. Increasing the optical input power to and reducing the length of the DCF segment thus both improves bit error rate of the system and reduces the cost for compensating for dispersion.

Abstract: A wireless electronic module includes a folded monopole antenna having an antenna port impedance which is reactive at the RF frequency of operation and which conjugately matches the reactive impedance of the electronic circuit which connects to the antenna port. A grounded shield is interposed between the antenna and the electronic circuit to reduce RF losses at the antenna.

Abstract: A duplex radio communication system includes an Interrogator which generates a first modulated signal by modulating a first information signal onto a radio carrier signal. The Interrogator transmits the first modulated signal to at least one remote Tag of the system. The remote Tag receives and processes the first modulated signal received at its Antenna. A Backscatter Modulator uses a second information signal to modulate the reflection of the first modulated signal from the Antenna, the reflected signal being a second modulated signal. The Interrogator receives and demodulates the second modulated signal to obtain the second information signal.

Abstract: A radio communication system includes an Interrogator for generating and transmitting a first modulated signal by modulating a first information signal onto a radio carrier signal, the first information signal indicating in which of multiple response modes a receiving Tag should respond. One or more Tags of the system receive the first modulated signal and decode it to obtain the first information signal. A Backscatter Modulator modulates the reflection of the first modulated signal using a second information signal whose content, data rate, or modulation is determined by said first information signal, thereby forming a second modulated signal. The Interrogator receives and demodulates the second modulated signal to obtain the indicated second information signal.

Abstract: A modulated backscatter communication system (e.g., an Electronic Shelf Label (ESL) system) includes a central node (e.g., a ceiling node) and one or more remote nodes (e.g., ESL tags). The central node transmits a downlink radio signal which is reflectively modulated at a remote node to produce a modulated reflected radio signal. At the remote node, a precise-frequency subcarrier signal is modulated with an uplink information signal to produce a modulated signal which is used to produce the modulated reflected radio signal. At the central node, the modulated reflected radio signal is received, detected and narrowband filtered to obtain the modulated subcarrier signal which is then demodulated to obtain the uplink information signal, with great immunity to close to carrier downlink radio noise and fluorescent light backscatter interference.

Abstract: An apparatus and method enables a user to control the selection of electronic multimedia services to be provided to the user by one or more servers over a communication medium. The apparatus includes a scanner for reading marks on an object and for communicating a request signal, having an object code representing the read marks, to a user interface. The interface receives the request signal and transmits to the servers a request command including an interface identification code and the object code which is used to select the desired electronic multimedia service. The servers identify the selected electronic multimedia service using the object code. The interface then enables the selected electronic multimedia service transmitted from the servers to be received by the user's receiver.

Abstract: A method and a system are provided to determine the optimum non-congested path to connect two termination points on a distributing frame with a specific type of jumper cable. The length of the jumper cable to be routed through the path is calculated and subsequently a measurement of the same cable and associated slack is displayed on a screen along with the non-congested path with a representation of the cable and slack therein.

Abstract: An apparatus and method provides optical multiple wavelength signals using a single optical broadband source to generate many independent optical wavelength channels. An optical transmitter includes a pulse chirping device which separates the frequency components of periodic optical pulses in the time domain forming separate wavelength channels which are separately modulated by a high-speed broadband optical modulator. A receiver includes a passive splitter to separate the individual wavelength channels. The chirped-pulse transmitter can then be conveniently adjusted to provide optimum overlap of wavelength channels with the modulating channel spectra.

Abstract: A wireless communications system is arranged to provide data communications services, including error recovery, between at least one wireless end-user device and at least one one base station. The wireless end user device(s) receives(s) from the base station(s) unsolicited messages indicative of the status of data packets received by the base station(s). The wireless end-user device(s) transmit acknowledgement and request for retransmission messages only upon request, or when all the packets within a block of such packets have been received.

Abstract: A communication apparatus (e.g., a fax apparatus) provides secure message transmission by sending messages having an unrestricted portion (e.g., a header) and a restricted portion (e.g., the body of the message). The unrestricted portion is always outputted at the receiving apparatus; however, access to the restricted portion is provided only in response to receiving predetermined information from a user (e.g., a message recipient). This information may include either the use of a password or the use of a PIN code following the insertion of a user's smart card into the receiving apparatus. If the restricted portion is encrypted, the user must either provide the decryption key to enable the receiving apparatus to decrypt the restricted message or his/her smart card must perform the actual decryption of the restricted message.

Abstract: An end-user communicating device and method for enabling a user-selected communications carrier network to download data into a RAM within the end-user communicating device in response to a telephone call initiated by a user of the end-user communicating device to the carrier network to access a database within the carrier network. The data includes a carrier access code that is used to establish intraLATA toll calls and exchange numbers included in an intraLATA toll calling area associated with origination information obtained during the telephone call, such as the telephone number of the end-user communicating device. The end-user communicating device prepends the carrier access code to subsequently dialed telephone numbers that contain one of the exchange numbers included in the intraLATA toll calling area.

Abstract: An optical isolator obtains reduced ripple due to Fabry-Perot reflections by using a polarization mode dispersion compensation element with first and second antireflection coatings designed to minimize reflections for first and second polarizations for first and second wavelengths.

Abstract: A communication system enables a system controller to allocate to a first system endpoint (e.g., application processor) control over one or more components of a second system endpoint (e.g., terminal). In response to a valid control request signal received from the first endpoint identifying one or more components at the second endpoint over which control is requested, the controller sends an acknowledgment signal to the first endpoint indicating that control over the identified component(s) has been allocated to the first endpoint. In response to the acknowledgment signal, an endpoint interface enables the first endpoint to directly communicate with the second endpoint using a first endpoint originated control signal which simulates a controller originated control signal for controlling the identified components at the second endpoint.

Abstract: A communication network (e.g., a coax network or an optical fiber network) comprises a signal distribution network (e.g., fiber node FN) for transmitting communication signals downstream over a first communication path to a plurality of end user apparatuses connected thereto. At least one end user apparatus is arranged for sending the return signals downstream over at least part of the first communication path to a converter apparatus which collects the return signals and converts them to an upstream signal for transmission over a second separate communication path to the distribution unit.

Abstract: A multi-media messaging system enables a user to select the communication format for communications between the system and the user. This enables the user to direct the system to convert the communication format of a stored message for the user from a first format (e.g. video) to a second format (e.g. audio). Another feature enables a user to change the language of the outputted message to be different from the language of the stored message. The system also enables a user to input a message in a first language and have the system translate it to a second language and then store it at a user selected location in memory.