Abstract: A fiber-coax network (30) includes feeder fiber (14) from a central office/headend (10) to a distribution node (32). At the distribution node, the transmissions are routed and distributed via successively a cable-coax node (16), a first PON node (36), and a second PON node (84). Each PON node comprises one or more passive optic component such as an optic splitter or wavelength division multiplexer (WDM). The cable-coax node provides broadcast CATV to subscribers via a coax distribution network (18) having spaced line extension amplifiers (LEAs) (26) in order to service more subscribers. The first PON node (36) provides switched telecommunication services (including ISDN) to subscribers via distribution fibers (38) which terminate at respective optic network units (ONUs) (40) that are co-located with an LEA (26) and connect to the coax distribution network downstream of the LEA (26).

Abstract: A switchable wavelength router has a first birefringent element that decomposes and spatially separates an incoming WDM optical signal into two orthogonally-polarized beams. A first polarization rotator selectably rotates the polarization of one of the beams to match the polarization of other beam, based on an external control signal. A wavelength filter (e.g., stacked waveplates) provides a polarization-dependent optical transmission function such that the first beam decomposes into third and fourth orthogonal beams, and the second beam decomposes into fifth and sixth orthogonal beams. The third and fifth beams carry a first spectral band at a first polarization and the fourth and sixth beams carry a second spectral band at an orthogonal polarization. A second birefringent element spatially separates these four beams into four horizontally polarized and vertically polarized components.

Abstract: In an optical fiber telecommunications network for providing both narrowband telephony signals and broadband video services over a single optical fiber using a single optical carrier, an optical distribution shelf includes a plurality of optical distribution units and interface units for interfacing with a controlling microprocessor. The optical distribution units receive baseband TDM telephony signals in serial format and the broadband video signals and function to frequency division multiplex the broadband video signals with the baseband telephony signals. The multiplexed signal is used to frequency modulate an optical carrier for transmission on a single optical fiber.

Abstract: An optical communication scheme is carried out by using a network having a plurality of nodes, a first network medium connected to a first group of the nodes, and a second network medium for transmitting control signals and connected to a second group of nodes. When initiating data transmission, any of the nodes transmits a transmission signal to the first network medium, and a receiving node that has received the signal loops-back the same signal to the second network medium thereby communicating information as to a state of congestion at the receiving node. A network for large volume data transmission can be realized by simple hardware and the state of congestion can be controlled using a simple method.

Abstract: Disclosed is a radio apparatus in a synchronous digital hierarchy (SDH) network in which a radio transmission line having a plurality of radio lines is installed between optical transmission lines each having a plurality of optical lines. The radio apparatus includes a plurality of channel boards, each of which is provided between an optical line and a radio line, for transmitting an optical signal received from the optical line to the radio line and transmitting a signal received from the radio line to the optical line, a setting unit, which is provided to be shared by each channel board, for attaching, per channel board, priority value to clock contained in each signal sent in via an optical line and a radio line, and for setting, per channel board, whether the clock of each priority value is to be outputted or not, and an equipment-clock decision unit for deciding a clock shared by the entire apparatus.

Abstract: An optical space communication apparatus for communicating by propagating a light signal in free space, including a multiplexer for multiplexing a first pilot signal with a transmission signal, a first converter for converting a first electric signal from the multiplexer into a first light signal, a transmitting optical system for transmitting the first light signal to a party apparatus, a receiving optical system for receiving a second light signal including a second pilot signal, having been transmitted from the party apparatus, a second converter for converting the second light signal into a second electric signal, a first band-pass filter having a pass region including a frequency of the second pilot signal, a first detector for detecting the second electric signal having passed through the first band-pass filter, a second band-pass filter having a pass region not including the frequency of the second pilot signal, a second detector for detecting the second electric signal having passed through the second

Abstract: The invention relates to the control of soliton-soliton interaction through the application of a positive phase shift. For each soliton width there is a critical phase modulation level above which soliton-soliton interaction can be virtually eliminated. This enables the spacing between adjacent solitons to be reduced, increasing the system bandwidth even for long transmission distances. The invention finds application in submarine and other long haul systems.

Abstract: A communications system has a base center with radio transceivers for providing a number of radio frequency (RF) communications links and a plurality of fixed radio ports through which RF signals can be transmitted and received over the air. A fiber optic network interconnects the RF transceivers and the fixed radio ports and carries the RF signals by means of optical signals. There is a plurality of radio/optical interfaces by which RF signals can be modulated onto and demodulated from one or more optical signals, between the RF transceivers and the fiber optic network, and between the fiber optic network and the fixed radio ports. A matrix switch selectively interconnects the transceivers and the radio ports through the fiber optic network.

Abstract: An optical wavelength demultiplexer comprises a monomodal incoming waveguide (1) for an incoming optical signal (S(.lambda..sub.1, .lambda..sub.2, .lambda..sub.3, .lambda..sub.4)) being propagated in fundamental guided modes having different polarisations (TE and TM), a conversion device (22) for converting the fundamental modes of one of the polarisations in first-order modes of the other polarisation, a divergence area (23) in which after conversion the incoming signal enters and diverges, a phased array (3) of curved monomodal waveguides provided with an entrance plane (7) and an exit plane (S), for receiving and further guiding the diverging optical signals, a convergence area (32) in which optical signals exiting at the exit plane (8) converge into signal beams (S(.lambda..sub.i)) converging into separate wavelength-dependent focuses (F.sub.i), and exiting bimodal waveguides (33(i)) joining to said focuses (Fi), thereby providing polarisation independent operation.

Abstract: A lensing system is provided for coupling light from one optical fiber to another through a plurality of graded index (GRIN) lenses. The system is capable of coupling light of two significantly different wavelengths in a relatively efficient manner. More specifically, a first GRIN lens having at least two ports on an outwardly facing end face is provided for coupling light of one of the wavelenghts from one of the at least two ports to another of the at least two ports. A second GRIN lens typically being about one half pitch, having an end face juxtaposed to an end face of the first GRIN lens, is provided for, in combination with the first lens, adjusting for differences in the two significantly different wavelengths, so that light will efficiently be coupled between a third graded index lens and the first graded index lens that are of different lengths to accommodate for the different wavelengths of light.

Abstract: An optical interconnect for use with SIMD processors, including holographic-optical elements, dove prisms, beamsplitters and a processor. Laser diodes, with each operating at a different wavelength, generate coherent-light beams at different wavelengths. A fiber combiner, an optical fiber and a fiber splitter are connected to divide output light from the laser diodes into equal path lengths. The output light is modulated by data from a respective SIMD processor. The output light forms an input ring at an input plane. Each holographic-optical element reflects only one wavelength of the output light. Dove prisms perform certain fixed interconnections. Beamsplitters reflect the light from the selected optical channel to an output-ring array.

Abstract: A compact, low-cost combined transmitting/receiving optical communications module, which is suitable for use in a TCM system and which is capable of normal operation over a particularly wide temperature range in optical communications equipment, is provided. The optical transmitting/receiving section for this purpose has a laser diode which outputs a transmitted optical signal, a combined monitor/receiving photodiode which not only monitors the optical output signal from the laser diode during a transmitting period, but also receives the input optical signal from the transmission path during the receiving period, and an optical mixer/divider which performs transmitting/receiving mixing and dividing between the transmission path, the laser diode, and the photodiode.

Abstract: A method and device for automatically and accurately measuring a noise figure of an optical amplifier are disclosed. In the method, light pulses which have different wavelengths .lambda..sub.1 .about..lambda..sub.n and have a period shorter than a time constant of extinction of the optical amplifier are generated. The light pulses thus generate are supplied to the optical amplifier. Powers P.sub.AMP1 .about.P.sub.AMPn of amplified lights outputted from the optical amplifier which correspond to the light pulses and have the wavelength .lambda..sub.1 .about..lambda..sub.n and powers P.sub.ASE1 .about.P.sub.ASEn of lights which have the wavelength .lambda..sub.1 .about..lambda..sub.n and are outputted from the optical amplifier when the amplified lights are not outputted from the optical amplifier are measured. Noise figures NF.sub.1 .about.NF.sub.n at the wavelengths .lambda..sub.1 .about..lambda..sub.n the optical amplifier are calculated according to the following equation.NF.sub.k =(P.sub.ASEk /h.nu..sub.

Abstract: The invention has the object of offering a phase synchronization system for wavelength division multiplexed bi-directional communications systems which can perform high-precision phase synchronization between a master device and a slave device without being affected by chromatic dispersion within the optical transmission medium. FIG. 1 is a block diagram showing the structure of an embodiment of the phase synchronization system of the invention. The phase synchronization system switches between phase difference measurement between optical signals of two different wavelengths which propagate in opposite directions and phase difference measurement between optical signals of the two different wavelengths which propagate in the same direction. By comparing the data indicating the phase difference, the system determines the delay time between the master device and the slave device.

Abstract: A data transmitter (12) transmits parallel data as light pulses over multiple optical channels (14). A data receiver (16) converts the light pulses back to a voltage level and compares the voltage level to a reference capacitor voltage (42). The capacitor voltage should maintain a mid-range value for proper noise margin in detecting logic ones and logic zeroes. Any long series of consecutive logic ones or zeroes causes the capacitor voltage to charge or discharge toward the same level as the data voltage, which causes data errors. To prevent the data errors, the data is encoded (18) by inverting certain bits to break up the long series of consecutive logic states. The encoding information is transmitted as a transmitted clock to the data receiver over another fiber optic channel. The decoding information is retrieved (20) so that the encoded data can be converted back to proper logic states.

Abstract: An optical transmission system accomplishes optical transmission over a long distance by combining a multiplexing line terminal with optical amplifiers, linear repeaters, and regenerators with optical amplifiers combined together. The system also accomplishes the optical transmission over a short distance by directly connecting the linear terminals therebetween, with an electric-to-optic converter replaced by an electric-to-optic converter having a semiconductor amplifier, with an optic-to-electric converter by an optic-to-electric converter having an avalanche photodiode as light receiver, and with no use of any optical booster amplifier and optical preamplifier in the multiplexing line terminal. With these, the optical transmission system can be easily constructed depending on the transmission distance required.

Abstract: An infrared communications adapter (10) is provided having a two part housing (22, 24) that snaps together to form a housing assembly (12) having an interior cavity (30). The interior cavity contains a circuit board (32) having communications circuitry and components thereon, including light emitting diodes (42, 44, 46) for indicating operating status of the unit and a photodiode array (34) for receiving and transmitting infrared signals. The adapter (10) includes a light pipe (50) having three light conducting channels (204, 206, 208) that conduct light from the three light emitting diodes (42, 44, 46) to viewing facets (190, 192, 194) on the light pipe that extend through openings in the housing (12). A lens (20) is arranged in a front end of the housing directly in front of the photodiode array (34). An articulated coupling 60 removably couples a stand (14) to the housing assembly (12) and permits aiming of the unit for receiving and transmitting the infrared signals.

Abstract: In an image processing apparatus for subjecting a desired image processing area of an original to desired processing to obtain an output image, it is so arranged that the desired area is bounded by a line of a color corresponding to the type of processing. This is read into the apparatus, which is then made to execute copying processing.

Abstract: A generalized connection network includes a first and second sub-network interconnected by a branching circuit having N inputs and N outputs. The branching circuit has N, two-state branching elements interconnected so as to be able to replicate a signal coupled to any one of the inputs to each of up to N outputs. The cyclic connection scheme provided by an additional two-state switch permits a net reduction in the total number of two-state switches necessary to form a generalized connection network.

Abstract: A system and method for multi-wavelength modulated optical communication uses the same optical fiber without the use of multiple tuned lasers. A transmitter includes an optical comb generator and a digital modulator. The optical comb generator generates a broad spectrum of wavelengths using a white noise generator. A Fabry-Perot cavity filters the wavelengths to form a set of equally spaced resonances lambda-1 . . . lambda-n. The comb generator is locked to a particular wave length by comparing each carrier or the composite mean of the carriers to an optical reference. An error signal is generated and fed back into the into comb generator. The resonances are split into n-channels using a tree splitter. Each channel is modulated in the digital modulator. The channels are summed as an optical signal and amplified to ensure proper power levels prior to being fed to an optical fiber.