Abstract: An infrared channel includes an IR transmitter circuit (302) and an IR receiver circuit (304). The transmitter circuit encodes data packets (400) which include a precursor segment, a synchronization segment, and a data field, the data field including data words, which words are bytes of data encoded by adding ones complement data bits and interleaving data subfields. The data fields are for infrared emission by the light source. A receiver circuit processor (316 or 508) is coupled to input samples to detect the presence of a precursor during a predetermined time period, and sleeping for a time interval, between inputting samples, which is substantially longer than the predetermined time period. The transmitter circuit transmits the precursor for a period of time at least as long as the sleep interval.

Abstract: There is provided an optical transmitting device with which signal light can be blocked only in the optical path having a displaced or removed optical connector without affecting the remaining optical paths.

Abstract: A prior art optical transmitter for an optical communication system having a radio system connected thereto comprises a DFB laser, an optical modulator, a signal source, and an optical filter. This optical transmitter transmits light which is not modulated by an intelligence signal. It is disadvantageous in that the optical filter and the DFB laser must be matched. An embodiment of the optical transmitter according to the invention comprises a light source (1), an optical modulator (2), and a control unit (3) which controls the light source (1) and the modulator (2) in such a way that the light emerging at the output (5) of the modulator (2) is modulated with an intelligence signal.

Abstract: A circuit arrangement for a light signal receiver for receiving and recognizing light signals which are transmitted in a pulsed manner and to which ambient light of an undefinable intensity is parasitically superimposed. The circuit arrangement contains a two-pole light sensor and, for each terminal pole of the light sensor, a separate current-voltage converter for direct current is provided. The current-voltage converters have identical transmission behavior. Each terminal pole of the light sensor is connected to an identical signal input of a current-voltage converter. The current-voltage converters are connected as amplifying filters and are negative feedback-connected in terms of direct current and in a frequency-dependent manner so strongly via the input at which the terminal pole of the light sensor is located that the d.c. voltage at the terminal poles of the light sensor is constant independently from the intensity of the parasitic light.

Abstract: To simplify the connection protocols of an optical communication network using wavelength division multiplexing and to increase the throughput of the network, each node sends messages on a specific wavelength and associates destination labels with them. A network controller receives the messages and the labels and forwards the messages on the receive wavelength of their destination node(s). Applications include local area networks.

Abstract: An optical transceiver receives first light having a first wavelength and also receives second light having a second wavelength. The optical transceiver has a first surface for transmitting the first light along a first path and a second surface for reflecting the second light along or from the first path. The optical transceiver also receives third light having the first wavelength, and the first surface reflects the third light along a second path. The first and second surfaces may be combined as one surface.

Abstract: In order to provide an optical transmitter applicable for a transmission speed range higher than 1 Gb/s without transmission quality degradation, the embodiment of the invention comprises a flipflop having a set terminal supplied with a transmission signal and a variable delay circuit for delaying an inverse output of the flipflop to be supplied to a reset terminal of the flipflop, for equalizing pulse width of the laser light with that of the transmission signal.

Abstract: A reconfigurable ring architecture for RF transport over fibers which eliminates the need for multiple pairs of fibers to serve multiple microcells and the need for backup communications lines as a result of system failure due to a fiber break. The ring architecture has a plurality of remote units which are interconnected to a host unit in a serial fashion. The host unit transmits signals to the plurality of remote units and receives signals from the plurality of remote units. Each of the remote units having photodetectors for receiving the transmitted signals and an antenna/transmitter for receiving other signals from another source; a splitter for splitting the transmitted signals into two parts, one part of the signals being output from the remote unit and the other part of the signals being transferred to adjacent remote units and then back to the host unit; and a transmitter for transferring the other signals from the remote unit to adjacent remote units and then back to the host unit.

Abstract: An optical transmission system accomplishes optical transmission to 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 to 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: The object of the present invention is to provide an optical transmitter which enables the reduction of the strong dependency of the transmission characteristic on the high-speed polarization scrambler driving signal phase. The light outputted from a light source is converted to a RZ pulse by an electro-absorption modulator. The RZ pulse is modulated by a data modulator, and the polarization thereof is scrambled in a high-speed electro-optic polarization scrambler and outputted from the output terminal thereof. Since, in the present invention, the light is once changed to a RZ pulse, the strong dependency of the optical signal transmission characteristic on the high-speed polarization scrambler driving signal phase can be reduced. Further, if the phase of the RZ pulse in the NRZ modulation signal is made to synchronize with the rising edge or the falling edge of the NRZ signal, the dependency on the high-speed polarization scrambler driving signal phase can be further reduced.

Abstract: The invention provides a multi-wavelength optical batch amplification apparatus wherein, upon batch amplification of a multi-wavelength input optical signal, the powers of optical signals on the input and output sides of an optical amplifier are monitored totally or individually to control the powers of optical signals of the output optical signal of the optical amplifier so that they may be fixed equally.

Abstract: A compact infrared identification and communication assembly, including a transponder device and at least one interrogator device, is provided. Each device includes a housing having an opening therein through which light may be received or emitted. The opening has a spectral filter mounted therein which permits only a specific frequency band of incident light to pass into and out from the housing. A dichroic beam splitter is mounted in the housing, aligned with the spectral filter, for reflecting and transmitting separate selected portions of the specific frequency band. A photodiode is aligned with the beam splitter, thereby receiving light from one of the separate portions, for example the transmitted portion. The photodiode converts its received light into an electrical signal which is subsequently converted into a form which a user may easily understand, for example an LED display.

Abstract: A programmable wavelength router having a plurality of cascaded stages where each stage receives one or more optical signals comprising a plurality of wavelength division multiplexed (WDM) channels. Each stage divides the received optical signals into divided optical signals comprising a subset of the channels and spatially positions the divided optical signals in response to a control signal applied to each stage. Preferably each stage divides a received WDM signal into two subsets that are either single channel or WDM signals. A final stage outputs optical signals at desired locations. In this manner, 2.sup.N optical signals in a WDM signal can be spatially separated and permuted using N control signals.

Abstract: Methods and apparati for spatially encoding and decoding spread spectrum communication signals using broad band light sources are disclosed. The encoding algorithms involve the use of orthogonal spatial wavelets, which are preferably discrete attenuation functions of light from different sources so that the discrete attenuation function is imposed upon the spectrum of the light source. The function may be used either merely for providing an encoded channel or by providing a second mask that may be, for example, the complement of the discrete attenuation function so that the light beam is discrete with the first attenuation function.

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 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: A wavelength division multiplex communication system comprises a head station (2) and a plurality of terminal stations (1) interconnected by an optical fibre cable (3). The head station (2) transmits continuous wave modulated wavelengths (.lambda..sub.1 -.lambda..sub.k), and a signalling wavelength (.lambda..sub.0) which is used to indicate, in each time slot, which wavelengths in the following time slot are available for transmission. Each terminal station (1) is arranged to receive the signalling wavelength, to determine therefrom whether the next time slot contains any data packets for that terminal station and, if so, to receive the packets. The terminal station (1) is arranged, if it has a data packet to transmit, to determine from the signalling wavelength whether the next time slot already contains data packets for the destination station and, if so, to avoid data collision by not transmitting its own data packet. The terminal station (1) then determines a free wavelength (.lambda..sub.

Abstract: A passive optical network for the downstream dense wavelength division multiplexing communication of data between a host terminal complex (HTC) and a plurality of optical network units (ONUs), and for the upstream communication of data from the ONUs to the HTC. The network includes a routing device for distributing downstream data signals contained in a common frequency band among a plurality of fiber drop lines for providing a corresponding wavelength to a corresponding ONU. The routing device also combines upstream data signals contained in a frequency band other than the downstream common frequency band, which are input to the routing device on the plurality of fiber drop lines, to a multi-wavelength signal which is provided to the HTC. In a preferred embodiment, the upstream data signals are output by the routing device to a broadcast port.

Abstract: An optical transmission system accomplishes optical transmission to 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 to 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-toelectric converter by an optic-to-electric converter having an avalanche photodiode as light receiver, an 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: A branch circuit is formed by forming an optical filter by means of connecting a wavelength selective reflector to between two units of directional coupler and further assembling three units of the optical filter.

Abstract: An optical, transmitter with a stabilized operating point for an optical transmitter, especially for that including a Mach-Zehnder optical modulator, is disclosed. An optical modulator is provided which modulates a light beam from a light source according to a driving voltage from a drive circuit. An operating point stabilizing circuit is provided which detects a drift in the characteristic curve from the optical modulator and controls the optical modulator to bring the operating point to a specified position. Deterioration in the waveform of the output optical signal due to the operating point drift is thereby prevented without depending on the input signal. Further, by performing an operating point shift under specific conditions, deterioration in the waveform due to wavelength dispersion can be effectively prevented, whether the sign of the wavelength dispersion is positive or negative.