Abstract: A high-speed wireless LAN system is disclosed.

Abstract: WDM optical tranmsmission equipment with redundant configuration includes a plurality of tranmitters. Each tranmitter includes active and standby panels including active and standby optical transmission circuits respectively having active and standby attenuators for controlling an attenuation amount of each output of the active and standby optical transmission circuits; and a coupler combining the outputs of the active and standby attenuators.

Abstract: A transmitter subsystem generates an optical signal which contains multiple subbands of information. The subbands have different polarizations. For example, in one approach, two or more optical transmitters generate optical signals which have different polarizations. An optical combiner optically combines the optical signals into a composite optical signal for transmission across an optical fiber. In another aspect, each optical transmitter generates an optical signal containing both a lower optical sideband and an upper optical sideband (i.e., a double sideband optical signal). An optical filter selects the upper optical sideband of one optical signal and the lower optical sideband of another optical signal to produce a composite optical signal.

Abstract: An optical triplexer design is described in which external optical signals at a first wavelength range propagate through a laser source. The laser source provides optical signals having a second wavelength range. The triplexer features a photodetector for providing intensity feedback signals to the lasers source and a dense wavelength division multiplexer for demultiplexing the external optical.

Abstract: An optically amplified wavelength division multiplexing network has the functionality to add/drop channels at the optical add/drop multiplexing (OADM) nodes. The OADM node includes a receiver amplifier, an OADM module, and a transmitter amplifier. Once the OADM node detects a loss of signal (LOS) due to a fiber cut or network element failure upstream, the receiver amplifier is kept in operation as a noise source. The output of the receiver amplifier is immediately raised by increasing pump power to compensate for the LOS. The noise power received at the transmitter amplifier from the receiver amplifier is substantially equal to the signal power expected before LOS. The transient effect of downstream optical amplifiers is therefore completely suppressed and the inter-channel stimulated Raman scattering (SRS) induced spectrum tilt does not change. After the noise power is raised, the receiver amplifier may be shut down at a speed much slower than the speed of downstream amplifier control circuitry.

Abstract: An IrDA module is coupled to a tapped inductor and makes both IrDA and remote control (RC) transmissions. The IrDA module includes a transmitter LED and a field effect transistor (FET) switch. The inductor has a first lead, a second lead and a tap. The first lead is coupled to a battery voltage, and the tap is coupled through a resistor to the LED anode. The drain of the FET switch is coupled to both the LED cathode and the second lead of the inductor. The location of the tap on the inductor is chosen such that the voltage drop across the LED when the FET switch is turned on and before the inductor saturates results in a desired IrDA LED drive current without using current-limiting resistors that can dissipate power. After the inductor saturates, the voltage drop across the LED results in a larger RC LED drive current.

Abstract: A method for the adaptive adjustment of a PMD compensator in optical fiber communication systems comprises the steps of taking the signal at the compensator output and extracting the components y1(t) and y2(t) on the two orthogonal polarizations, computing the signal y(t)=[y1(t)]2+[y2(t)]2, sampling the signal y(t) at instants tk=kT with T=symbol interval to obtain samples y(tk), computing the mean square error e(k)=y(tk)?u(k) with u(k) equal to the symbol transmitted, and adjusting the parameters of the compensator to seek to minimize e(k).

Abstract: Provided is an apparatus for testing the performance of an optical transceiver by referencing various performance clocks provided by an OTU2 signal connection transceiver and an STM-64/OC-192 signal. The apparatus for testing performance of an optical transceiver includes: a transmitter/receiver reference clock selector for selecting one of various transmitter/receiver reference clocks provided by an STM-64/OC-192 connection optical transceiver or an OTN connection optical transceiver; a transmitter test reference clock selection switch for selecting a receiver data synchronous clock provided by the transceivers or the selected transmitter/receiver reference clock as a transmitter test reference clock; and a receiver test reference clock selection switch for selecting a transmitter supervisory clock provided by the transceivers or the selected transmitter/receiver reference clock as a receiver test reference clock.

Abstract: A receiving circuit stops a one shot timer from generating an output signal immediately after the output signal is outputted to an external entity until a predetermined stretch time elapses. With this arrangement, the receiving circuit will not generate a new output signal even if (i) noises generated by a voltage fluctuation of the output signal appear on an amplified signal immediately after the output signal is outputted (at the end of the output), and (ii) the value of the amplified signal exceeds a threshold value. Therefore, the receiving circuit can make sure that an unnecessary output signal will not be generated due to the noises.

Abstract: A WDM transmission system is provided which can multiplex/demultiplex and transmit wavelength division multiplexing signals, where signal lights have a different signal bandwidth, in a status without much deterioration of transmission quality. In the WDM transmission system, an optical receiver includes a demultiplexing unit which demultiplexes the wavelength division multiplexing signals and outputs the demultiplexed signal lights from a plurality of output ports, wherein each output port has transmission characteristics to be set such that the bandwidth of the transmission band where the light transmits and the bandwidth of the non-transmission band where light does not transmit are different, and the transmission band substantially matches with the signal band of the signal lights that are output from the output port out of the received wavelength division multiplexing signals.

Abstract: An optical wavelength division multiplexing network has a multi-level structure where a plurality of optical network units (ONUs) are connected to a lowest-level network. A node apparatus connected to networks other than the lowest-level network includes (a) passive optical components to branch optical signals from a higher-level network to a lower-level network, and couple optical signals from the lower-level network to the higher-level network, and (b) optical amplifiers for the optical signals. A node apparatus connected to the lowest-level network includes (a) an optical multiplexer/de-multiplexer to de-multiplex optical signals from the higher-level network, selectively output an optical signal to each ONU, and multiplex wave-length specific optical signals from the ONUs into a multiplexed optical signal, and (b) optical amplifiers for the optical signals.

Abstract: According the invention, a multiplexed light composed of a signal light of a signal wavelength, and a first route control light of a first route control wavelength different from the signal wavelength or a second route control light of a second route control wavelength different from the signal light and the first route control wavelength is incident to a demultiplexer. The demultiplexer demultiplexes the signal light of the signal wavelength, the first route control light, and the second route control light from the multiplexed light. An interferometer optical switch outputs the signal light from first output port according to the first route control light, and outputs the signal light from second output port according to the second route control light.

Abstract: An Ethernet passive optical network provides a subscriber with a high speed and large capacity data service and a real time digital broadcast/video service. The network includes an optical line terminal for frame-multiplexing broadcast/video signals, which are obtained by performing a switching operation and a time-slot multiplexing with respect to a plurality of digital broadcast/video data delivered from external broadcasting vendors according to broadcast/video selection information delivered from each user, and communication data delivered through an Internet protocol network.

Abstract: An apparatus and method for processing a supervisory signal for optical network applications. The apparatus includes a subcarrier transmission system configured to receive a first supervisory signal and output a second supervisory signal, and an electrical-to-optical conversion system configured to receive the second supervisory signal and a first data signal and output a first optical signal. Additionally, the apparatus includes an optical-to-electrical conversion system configured to receive the first optical signal and output a first electrical signal and a second data signal, and a subcarrier reception system configured to receive the first electrical signal and output a third supervisory signal. The second supervisory signal is associated with a first subcarrier frequency. The first data signal is associated with a first data bandwidth, and the first data bandwidth includes a first data frequency. A ratio of the first subcarrier frequency to the first data frequency ranges from 0.8 to 1.

Abstract: It is an object of the present invention to provide a control technique for reducing wavelength dependence of wavelength dispersion values and also for suppressing a change in wavelength transmission characteristic with a temperature variation or the like, in a VIPA-type wavelength dispersion compensator.

Abstract: A wavelength division multiplexed self-healing passive optical network using a wavelength injection method includes a central office for coupling modulated multiplexed optical signals (MMOS) and broadband optical signals (BOS)for an upstream light source into one signal transmitted to a plurality of optical network units (ONUs) through a working main fiber and a protection main fiber. A remote node connects to the central office via the main fiber and protection main fiber and to the ONUs through working distribution fibers and protection distribution fibers. The remote node demultiplexes the MMOS and the (BOS) for an upstream light source. The remote node transmits demultiplexed signals to the ONUs, which receive the modulated optical signals and the BOS for an upstream light source which corresponds to predetermined ONUs, and demodulate the modulated optical signals, and modulate upstream optical signals via demultiplexed BOS for an upstream light source.

Abstract: An apparatus for generating a Carrier-Suppressed Return-to-Zero (CS-RZ) signal is disclosed. The apparatus includes a mixer, a Low Pass Filter (LPF), a driver amplifier and a single external modulator. The mixer generates a modulator input by mixing data with a half clock signal. The LPF band-limits the modulator input data into low frequency band data. The driver amplifier amplifies the modulator input data generated by the mixing of the mixer and the band-limiting of the LPF. The external modulator generates CS-RZ signal, in which the phases of adjacent pulses have been inverted, by applying bias voltage to the modulator input data to be placed at the null point of the transfer function of the external modulator.

Abstract: An adaptive optics system is provided. The system includes a light source, a pair of deformable mirrors and a detection module. The light source is configured to provide an outgoing beam. The outgoing beam has an amplitude and a phase. The first deformable mirror is configured to reflect the outgoing beam and adjust its associated amplitude. The second deformable mirror is configured to reflect the outgoing beam reflected from the first deformable mirror and adjust its associated phase. The detection module is configured to detect an incoming beam and the reflected outgoing beam from the second deformable mirror and generate certain signals. The signals are used to control the first and second deformable mirrors such that the amplitude of the outgoing beam is the same as that of the incoming beam and the phase of the outgoing beam is opposite that of the incoming beam.

Abstract: A communications system includes an optical receiver for receiving optical signals and for converting the optical signals into electrical signals, a transimpedance amplifier (“TIA”) for filtering the electrical signals, a limiting amplifier coupled with the TIA, an automatic threshold control (“ATC”) coupled with the TIA for providing a reference voltage for the limiting amplifier. The ATC further includes a common emitter circuit and an emitter follower circuit, wherein logic high signals and logical low signals in the electrical signals are determined based on the reference voltage output from the ATC.

Abstract: An optical receiver circuit comprising an optical converter circuit (38), comprising a photodiode and converting optical power into electrical power, a sensor circuit for deriving a control voltage VCONTR as a characteristic value of the electrical power output by the optical converter circuit (38); and an attenuator circuit (44) having a variable attenuation, the attenuation being controlled by the characteristic value of the electrical power output by the sensor circuit so as to obtain a constant output signal level of the optical receiver circuit. An output circuit is also provided and comprises a matching network (46), an amplifier stage (48) and an output transformer (50).