Abstract: Erbium doped fiber amplifiers (ERDAS) optically couple optical signals between free-space and fiber optic links of a terrestrial optical communication network. The optical gain of transmitting and receiving ERDAs is controlled to achieve good optical signal communication. Control occurs in response to signals received at the transmitting and receiving ends of the links. Control, status and management information may be communicated optically between link head stations. The physical position of transceivers at opposite ends of the link optical signal paths is also controlled.

Abstract: In a wavelength-division multiplexing transmission technique, a loss difference compensator for compensating a loss difference of an optical signal at each wavelength generated in a wavelength-division-multiplexed optical signal due to a wavelength-dependent transmission loss characteristic of an optical transmission line is disposed to the optical transmission line for transmitting the wavelength-division-multiplexed optical signal having a wide wavelength band in which optical signals at a plurality of wavelengths are wavelength-division-multiplexed to compensate the loss difference of the optical signal at each wavelength generated in the wavelength-division-multiplexed optical signal due to the wavelength-dependent transmission loss characteristic of the optical transmission line and a dispersion compensator, thereby transmitting the wavelength-division-multiplexed optical signal in a wide wavelength band for a long distance.

Abstract: A method and apparatus is provided for transmitting an optical signal having a total number of channels that are dividable into a prescribed number of wavebands. The method includes the step of generating a first series of optical signals corresponding to each of the wavebands. The first series of optical signals includes a plurality of optical channels, which are sequentially numbered from 1 to N from lowest to highest wavelength. Within each waveband, a state-of-polarization of predetermined odd-numbered channels is oriented to be substantially orthogonal to a state of polarization of predetermined even-numbered channels by directing the predetermined odd-numbered channels and the predetermined even-numbered channels through orthogonally polarizing inputs of a polarization coupler. The odd-numbered channels and the even-numbered channels within each waveband may be directed through first and second wavelength combiners, respectively, prior to orienting their states of polarization.

Abstract: A satellite has an optical communications device coupled to a satellite body. The optical communications device has a laser light generator, a first optically refracting device, and a second optically refracting device. The first and second optically refracting devices are coupled to a respective movement mechanism. The movement mechanisms are used to position the optically refracting devices with respect to each other. By rotating the optically refracting devices about a common axis, either independent of each other and/or locked together, the optical output may be directed to a desired location.

Abstract: A Method and System for Enabling Wireless Data Communications with Electronic Devices having Disparate Operating Systems is disclosed. Also disclosed is a system that compares the Infrared or RF communications configuration of an electronic appliance to a target profile, and then uploads the target configuration profile to the appliance, if necessary. The preferred device and system perform a functional testing on the wireless communications system of the electronic appliance, including the transceiver hardware and all device drivers and software stacks. Furthermore, the device of the present invention is able to adopt the target configuration from an electronic appliance by downloading it from one or more appliances. Still further, the device of the present invention is able to communicate with two or more electronic appliances simultaneously. The device and system of the present invention are operable independent of the BIOS of the electronic appliance(s) to be configured.

Abstract: An optical transmission device that can be applied to a wavelength-multiplexed optical transmission system includes a first part creating a supervisory control signal to be transmitted in optical formation together with an optical main signal, the supervisory control signal comprising a vector of elements respectively corresponding to wavelengths. The device further includes a second part converting a vector included in a supervisory control signal received from a remote optical transmission device into another vector by a process using a path matrix in the vector received forms diagonal elements of the path matrix, the above another vector being transmitted to a next stage in the wavelength-multiplexed optical transmission system.

Abstract: The present invention relates to an optical transmission device and an optical communication system applied to wavelength division multiplexing (WDM). The optical transmission device includes an optical multiplexer for wavelength division multiplexing a plurality of optical signals to generate WDM signal light and outputting the WDM signal light to an optical transmission line, a detecting unit for detecting a break of each optical signal according to the power of each optical signal, and a compensator for adding light having a predetermined wavelength to the WDM signal light when at least one of the optical signals is cut off. Through the structure of the present invention it becomes possible to prevent a deterioration in transmission quality in the case that the number of WDM channels is changed.

Abstract: An apparatus and method are provided for bit synchronization in an optical time division multiplexed communication system. The apparatus is couplable to an optical gate, such as an optical demultiplexer. The apparatus includes a programmable optical delay line couplable to an input clock; an optical synchronizer coupled to the programmable optical delay line and couplable to the optical gate; and a processor coupled to the programmable optical delay line and to the optical synchronizer. The processor includes program instructions to track bit synchronization between a clock pulse and a selected data bit during a communication session; and when a bit tracking range is approaching a predetermined limit, the processor having further instructions to interrupt the communication session, return the bit tracking range to a zero offset and correspondingly adjust a programmable delay, and resume the communication session.

Abstract: A message transmission system comprises a transmitter and receivers, the transmitter comprising a generator for generating a digital data signal representing a message, and an encoder for encoding the digital data in a serial code having a first and second frequencies representing respectively digital data signal first and second logic states. A modulator is connected to at least one source of visible light for modulating the intensity of light emitted by the light source with the serial code. The light emitted by the light source has two distinct intensities when the light intensity is modulated with the first and second frequencies. Each receiver comprises a detector sensitive to the visible light emitted by the light source for converting visible light emitted by the source into an electrical signal having two states depending on the intensity of the visible light detected. A decoder reconstructs the transmitted message from the electrical signal.

Abstract: One or more pieces of equipment of a hybrid fiber-coaxial (HFC) network has a frequency agile transponder connected thereto. Each frequency agile transponder includes a transmitter (T) and a receiver (R) which are connectable to a coaxial line of the HFC network. Bidirectional communications can occur between a controller and each frequency agile transponder via the HFC network. The frequency agile transponder has analog inputs/outputs connectable to test points of the one or more pieces of equipment of the HFC network. The frequency agile transponder can test the test points and supply to the controller the results of the test. The transmit and receive center frequencies of the transmitter and receiver of the frequency agile transponder can be selectively and remotely adjusted by the controller to avoid signals at carrier frequencies utilized to transmit program material, data signals and/or telephony signals.

Abstract: An infrared (IR) communication system is described in which a base unit for a cell can communicate with a plurality of infrared portable devices through distributed infrared receiver/transmitter (RT) modules over a plurality of channels using IR carrier signals. A call or signal processor, referred to as a radio exchange unit, and controlling communication of a cell, communicates with the base unit to place or receive calls with the IR portable devices. The communication occurs in standard communication frames divided into transmission and receiving segments with each segment further divided into slots and with the slots containing digital data, with each communication channel formed by a slot. Each transmission segment to an RT module is immediately followed by a responsive receiving segment.

Abstract: Data is transferred between a plurality of processors. A plurality of light beams is produced. The light beams have at a particular time a single wave length. The single wavelength is selected from a plurality of wavelengths. Each light beam is uniquely associated with a processor. Each processor selectively modulates data onto its light beam. At a particular time, the selected wavelength of the single wavelength and the processors modulating data onto their light beam is controlled. The plurality of light beams is received at an input ring array. The light beams from the input ring array are transferred to an output ring array. Each light beam is rotated. Each selected wavelength is uniquely associated with a particular rotation. A light beam is output to each processor from the output ring array.

Abstract: An improved access system for use in a Fiber-In-The-Loop (FITL) communications network is disclosed. The access system comprises a host digital terminal (HDT) and a plurality of subtending optical network units (ONUs). The digital signal processing (DSP) functions traditionally executed by line interface units (LIUs) within the ONUs are migrated to the HDT, rendering the individual ONUs simpler, cheaper and more reliable. This is made possible by the provision in each ONU of an oversampling codec for sampling (and conversion) of upstream and downstream data at a very high bit rate. The large bandwidths of the data communicated between the ONUs and the HDT are easily handled by the fiber optic medium therebetween.

Abstract: The invention relates to protection of an optical transmission connection. From the transmitting end of the connection, the same optical signal is transmitted along a first path and a second path to the receiving end, where the power level of the signal received from each path is monitored, and one of the paths is selected as the working path and the signal arriving from the said path is connected to the receiver, whereby the other path remains as a redundancy path. For the transmission connection to preserve an optimum performance also when the power level difference between the paths is varying, that path is at each time selected as the working path, where the received signal is considered at the moment in question to have the higher power level. The selection is always carried out when the power level difference between the signals reaches a predetermined threshold value, irrespective of the power level of the signal received at that time from the working path.

Abstract: A free space light multibeam network bridge apparatus receives free space light beam communication signals from free space light communication devices and routes the free space light beam communication signals to other free space light communication devices via a free space light network or to non-free space light destination devices via a telecommunications network. The free space light multibeam network bridge apparatus identifies the source of a free space light beam communication signal based on the position of the free space light beam communication signal on a sensor.

Abstract: A low-latency, high-bandwidth, hybrid TDM/WDM architecture for connecting processing nodes into a high-performance computing environment designed as a system area network is disclosed. Each node has a receiver for receiving optical communication within a fibre at all wavelength channels supported by the system simultaneously and individually. Each node also has a transmitter for transmitting at at least two wavelengths. One of the wavelengths is a default wavelength for the node. In order to transmit data, a node requests a channel and is provided with a transmit wavelength at which to transmit data. Other nodes receive the data and, when the recipient is the addressee of the data, the data is then forwarded to a computing device connected to the node or in communication therewith. The architecture provides robust communication with high bandwidth.

Abstract: When a branching unit combines a first optical signal transmitted from a branch station with a second optical signal which is different in power level from the first optical signal and is transmitted from a terminal station A or B in an optical add-drop system, the S/N ratio of the lower power level of the two different power levels decreases, thereby deteriorating the system performance. Therefore, a dummy light is transmitted together with an optical signal to adjust the power level of the optical signal. Otherwise, an optical attenuator or an active optical signal level adjustment unit is provided for the branching unit so that both optical signals to be combined can be equal in level.

Abstract: A method and apparatus for transmitting a wavelength division multiplexed (WDM) signal through an optical transmission line to reduce the effects of stimulated Brillouin scattering (SBS). The WDM signal includes a plurality of light signals multiplexed together. The WDM signal is transmitted through the optical transmission line so that the intensity per light signal is higher than an intensity threshold at which stimulated Brillouin scattering (SBS) occurs for a single light signal individually transmitted to the optical transmission line.

Abstract: Collisions between solitons in different frequency channels are one of the major sources of errors in transmission systems that utilize wavelength division multiplexing (WDM). Moreover, because standard transmission lines have lumped amplification, the four-wave mixing fields from soliton collisions grow uncontrollably, adding amplitude and timing jitter to the jitter due to ideal soliton collisions. These problems are addressed by using a specific dispersion map to implement dispersion management, by which it is possible to significantly reduce the collision-induced timing jitter and to improve system performance even in comparison with that provided by an ideal, exponentially decreasing dispersion fiber.

Abstract: A method and apparatus performing fault management in an optical communications system including a polarization mode dispersion (PMD) compensator. The method and apparatus utilizes a controller receiving notifications indicative of PMD in the system, as well as at least one indicator from a system device providing an indication of an attribute of the communication system. Such system devices include a receiver providing a Q factor and a bit error rate (BER) of an optical signal, and a signal-to-noise ratio meter providing an SNR of the optical signal. The method intelligently provides fault management by correlating the PMD notifications and system indicators to distinguish between fiber failure, PMD-related degradations, and failure of monitoring equipment itself.