Abstract: The high transmission capacity of an optical transmission path (about 200,000 km Mbit/s) is used, among others, to couple several data sources and data sinks to an optical waveguide. The task of the invention is to ensure the coupling in and out of several data streams to or from any path section of a (predetermined) optical transmission path. This task is fulfilled by a device for the parallel-serial conversion, and a device for the serial-parallel conversion of the data streams to the optical transmission path. The coupling in and out of the individual data streams is performed by optical modulators or optical expanders, which are incorporated into the optical transmission path. Several data streams are parallel-serial converted by means of additional incorporated optical time delay elements, which ensure the bit interlacing of the data streams (bit-interleaved).

Abstract: The invention provides an optical space switch device which provides variable interconnection of one- or two-dimensionally spatially multiplexed optical signals. The optical space switch device comprises a plurality of optical space switch stages stacked to form a multi-input multi-output optical space switch. Each of the optical space switch stages comprises a plurality of 2-input 2-output optical switches, each of which comprises a polarization control layer and an optical path shifting layer. The optical path shifting layer has a bypass mode in which it outputs beams of light along optical axes and an exchange mode in which it shifts beams of light by diffraction.

Abstract: A spatial synchronization method for an optical communications system includes the step of transmitting from a transmit aperture a pyramidal synchronizing profile so as to sequentially spatially register a user identification speckle pattern at a receive aperture. The iterative patterns in the pyramidal synchronizing profile detected by the receive array are processed and correlated with a library of respective user pyramidal synchronizing profiles so as to match and register the speckle pattern for a particular user. Registration of the user speckle pattern provides an offset value representing the spatial relation of a reference point of the user's pattern to a corresponding reference point of the receive aperture, which offset information is applied to a receive pattern processor so that the receive aperture is aligned with the transmitted speckle patterns.

Abstract: A rotary control device is provided comprising a light receptor (52), a plurality of light sources (54) radially spaced from the light receptor (52), a light director (14) having means for directing light from the light source (54) to the receptor (52) and means for rotating the director (14) thereby selectively directing light from the light sources (54) to the light receptor (52). In another aspect of the invention, the optical rotary device further comprises an isolator (56) made of opaque material which surrounds four sides of the light receptor (52) and four sides of the light sources (54). In a further aspect of the invention the light director includes a reflector (46) for directing the light from the light sources (54) to the light receptor (52).

Abstract: An optical communication unit includes a light emitting-receiving element provided in such a manner that an optical axis thereof is set perpendicular to an electric circuit substrate, a reflecting plate for changing a direction of the optical axis, and a filter. The reflecting plate is provide outside the filter so as to be freely rotatable around one end of the reflecting plate. Since the reflecting plate is arranged so as to be rotated to a position where the filter is covered when optical communication is not carried out, the filter can be protected from being scratched or accumulating dust, and the unit can be made thinner. On the other hand, when optical communication is carried out, by rotating the reflecting plate, the communication direction can be set as desired.

Abstract: A telecommunications switching device includes a plurality of ports and a plurality of switching units and a connecting circuit for connecting each of the ports to each of the switching units in turn. The connecting circuit includes a photonic channel separation circuit and a photonic space switching circuit.

Abstract: This invention relates to the use of Optical Time Domain Reflectrometry for locating fibre faults, e.g. breaks, in the transmission fibres associated with fibre amplifiers. Optical time Domain Reflectrometry measures the range to a fibre break by transmitting a pulse into the fibre. The returned signals are measured and timed and the timings are equivalent to a measurement of the range. In this invention, the laser pump used to drive the fibre amplifier is also used to generate the pulses to drive the Optical Time Domain Reflectrometry. This invention is particularly intended for use in the repeaters of a submarine telecommunications optical transmission system. These systems usually have a distress mode which is adopted in case of a malfunction, e.g. a broken fibre. The distress mode usually provides a channel for the transmission of distress information and the Optical Time Domain Reflectrometry information can be transmitted via this channel.

Abstract: In an optical transmitter and receiver device, a transmitter receives a transmitting data signal and drives a laser diode to make the laser diode emit an optical data signal representative of the transmitting data signal. The laser diode simultaneously emits a backward optical leakage signal. A photodiode is disposed at a rear side of the laser diode and detects the backward optical leakage signal as an optical monitoring signal to produce an electric monitoring signal. The transmitter receives the electrical monitoring signal to control an output power of the laser diode at a stabilized level. When the transmitter receives no transmitting data signal, the laser diode functions as an optical amplifier for an incoming optical data signal thereto and delivers an amplified optical data signal to the photodiode. The photodiode converts the amplified optical data signal to an electrical reception signal.

Abstract: A method and apparatus are provided for monitoring power loss in a telecommunications system. Power is received from a permanent power source. A loss of power from the permanent power source is detected. Responsive to the detection of loss of power, a message indicative of a power failure is transmitted at least once on an optical fiber, the message transmission being powered by a temporary power source.

Abstract: An optical pulse propogating in an optical guide of an electro-optic medium interacts with a coplanar RF traveling wave to shift the optical wavelength. The RF phase is resynchronized to the optical pulse phase with spatial periodicity to provide a desired phase relationship between RF and optical radiation. A unidirectional incremental wavelength shifter comprises a frequency multiplexer for soliton communication and a symmetrical sideband modulator of this type varies the spectral width of probe illumination in an atomic absorption spectrometer probe beam.

Abstract: An optical signal generator, an optical communication system, and a method for searching for a Fresnel reflection point in an optical transmission line make use of characteristic features of stimulated Brillouin scattering (SBS). In the optical signal generator, exciting light supplied to an optical transmission line, formed of a nonlinear optical medium, showing stimulated Brillouin scattering, is amplitude-modulated with an information signal. The threshold value for stimulated Brillouin scattering in the optical medium is positioned between a high level and a low level of the modulated waveform.

Abstract: An optical transmitter apparatus comprises a light source for optical signal transmission, an intensity modulator, a transmit signal generator and a signal generator. A transmit signal to be transmitted is supplied from the transmit signal generator to the intensity modulator, while a signal generated by the signal generator is supplied to the phase modulator. A light beam emitted from the light source passes through the intensity modulator and the phase modulator to be subsequently sent out as an optical signal for transmission with intensity thereof being modulated upon passing through the intensity modulator while spectrum thereof being spread by phase modulation which the optical signal undergoes upon passing through the phase modulator.

Abstract: A facsimile communication system including a first processing circuit, connected to receive a facsimile signal from a first facsimile device, for converting the analog voiceband facsimile signal into a digital code signal representing information carried in the analog voiceband signal, and for transmitting the digital code signal; a second processing circuit, connected to receive the transmitted digital code signal from the first processing circuit, for converting the received digital code signal into an analog voiceband facsimile signal; and a second facsimile device, connected to receive the analog voiceband facsimile signal from the second processing circuit. The digital code signal includes a digital code which is repeated in the digital code signal an integral number of times. In another embodiment, the digital code signal contains another binary code which represents the position, within a data field, when information was first detected by the first processing circuit.

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: An optical frequency division multiplexing network includes first optical communication paths connected to terminals, respectively, a second optical communication path connected to the outside and a node composed of a selection unit for selecting signals having optical frequencies to be sent to the plurality of terminals, respectively, from signals transmitted through the second optical communication path in optical frequency division multiplexing, a conversion unit for converting the selected signals into signals having a single optical frequency and an output unit for producing the converted signals to the terminals through the first optical communication paths, respectively.

Abstract: Novel structure and methods for tuning the local oscillator of an optical superheterodyne receiver are disclosed. In a first method, the value of the local oscillator frequency at which the maximum of the chronological average of the output signal from the demodulator occurs is used to set the local oscillator frequency. An alternate method first and second discriminators are used to receive the intermediate frequency signal. The separate discriminator characteristics of the first and second frequency discriminators are used in setting the local oscillator frequency.

Abstract: For communicating over optical routes, route monitoring and protection are provided. In routes carrying signals on each of a number of wave lengths a tapped fraction of the signal is demultiplexed and an individual wave length is detected for determining performance and for triggering switching to alternative monitored routes carrying the same signal. Switching of all wave lengths if one shows faulty, with either a single wave length or all wave lengths being monitored is shown. Performance of a long wave length component is employed to determine route quality for shorter wave lengths as well. In bi-directional communication systems, performance of a wave length moving in one direction through a route determines route quality for transmission in the other direction, as well. Progressive sampling and digitization of the tapped signal and comparison to a digitized reference enables high sensitivity of monitoring.

Abstract: The network according to the invention combines a circuit switching multicoloured optical network (R1) and a packet switching network (R2). The circuit switching network is adapted to transmit data at a high rate. The packet switching network is adapted to transmit data at an average rate. Control data are carried on the packet switching network. This provides more efficient transmission of data and effectively handles peak transmission rates. The invention has application to telecommunications.

Abstract: A logic processing apparatus comprises a plurality of integrated circuits, a multi-phase clock generator for distributing clock signals having different phases from one another to the respective integrated circuits, and a package, for air tight sealing the multi-phase clock generator and the plurality of integrated circuits, which has an optical signal transmissible window for transmitting the master clock signal to the multi-phase clock generator through the optical transmitting line.

Abstract: An optical transmission system, particularly useful for long-span, long haul, high data rate applications, The inventive system utilizes pulses with a width of at least 20% of the bit period. Instead of solitary pulses as in soliton systems, the system uses pulses which will eventually interact, but by selection of pulse widths according to bit rate and dispersion of the system the pulse will propagate for large distances. A particular modulation technique is described.