Abstract: In order to appropriately demultiplex the polarization multiplexed BPSK signal without using a training sequence and decreasing the resistance to a frequency offset, an optical receiver includes a coherent optical detection unit receiving an optical signal in which BPSK modulated carrier waves are polarization-multiplexed, performing coherent detection by mixing the received optical signal with local light, and outputting first electrical signals corresponding to the carrier waves; a butterfly FIR filter receiving the first electrical signals and extracting second electrical signals corresponding to each of the carrier waves from the first electrical signals; and a coefficient control unit for calculating a sum of respective phases of the second electrical signals output from the butterfly FIR filter, adaptively controlling tap coefficients of the butterfly FIR filter so that the calculated phase sum may become equal to 0 or ?, and outputting tap coefficients after being controlled to the butterfly FIR filter

Abstract: In a sampling clock synchronizing apparatus, an A/D converter converts an analog signal to a digital signal based on a sampling clock, and a processor compensates a band limitation due to spectral narrowing by filter characteristics of characteristics opposite to those of the spectral narrowing with respect to a signal produced from the A/D converter subjected to the spectral narrowing, and detects a phase shift in the sampling clock based on a signal after the compensation of the spectral narrowing and synchronizes sampling timing.

Abstract: A wavelength division multiplexed optical communication system includes a plurality of optical line terminals which may be part of separate in service networks, each having a line interface and an all-optical pass-through interface including a plurality of pass-through optical ports, and each also including a plurality of local optical ports which are connectable to client equipment and an optical multiplexer/demultiplexer for multiplexing/demultiplexing optical wavelengths. The optical multiplexer/demultiplexer may include one or more stages for inputting/outputting individual wavelengths or bands of a predetermined number of wavelengths, or a combination of bands and individual wavelengths.

Abstract: The various embodiments herein provide a method and system for protecting multiple work ODU failures using a higher capacity protect ODU in an Optical Transport Network. The method for protecting multiple work ODU failures in an Optical Transport Network comprising steps of detecting signal failures in at least one of a plurality of work ODUs, requesting for release of one or more time-slots for a defective work ODU and allocating the one or more time-slots of a low priority traffic from the protect ODU in an incremental manner of priority. The method apply a TPN based policy for defining lower ODUs, performs handshaking between the transmit and downstream ends using the protocol provided, defines the role and behavior of the various system components and the service requests and performs an automatic lockout of protection for the work ODU in which an UDI alarm is present.

Abstract: A method and a device for detecting Inband Optical Signal to Noise Ratio (OSNR) are provided in the present invention, wherein the method includes the following steps: obtaining a signal power PCW1 of a first optical signal at a transmitting end, a signal power PCW2 of a second optical signal at the transmitting end, and a total signal power PS; obtaining a ratio k1 of the PCW2 to the PS and a ratio k2 of the PCW1 to the PCW2 according to the PCW1, PCW2 and PS; obtaining a signal power P?CW1 of the first optical signal at a detection point and a signal power P?CW2 of the second optical signal at the detection point; obtaining a ratio K3 of the P?CW1 to the P?CW2 according to the P?CW1 and the P?CW2; and obtaining the Optical Signal to Noise Ratio according to the k1, k2, and k3.

Abstract: The present invention proposes a wavelength division multiplexing-passive optical network (WDM-PON) system which transmits downstream data to an optical network unit (ONU) as an optical line termination (OLT) receives seed light from a spectrum-sliced external light source module. One characteristic of the proposed WDM-PON system is that optical transmitters of the OLT and ONU are operated regardless of optical wavelength. Another characteristic of the proposed WDM-PON system is that a conventional TDMA-PON (E-PON or G-PON) ONU can be accommodated without a change.

Abstract: A device may include a component, a first switch, a repeater, and a second switch. The component may configure optical paths between ports. The component may comprise a first pair of optical ports connected to a first pair of optical fibers, and a second pair of optical ports connected to a second pair of optical fibers. The first switch may be configured to output one of two optical signals received by the first pair of optical ports from the first pair of optical fibers. The repeater may reshape or amplify the outputted optical signal. The second switch may be configured to direct the reshaped or amplified signal to one of the second pair of optical ports.

Abstract: An ONU includes a power-interruption detecting unit configured to detect power interruption of the ONU, a transmitting and receiving unit capable of being set in a power saving state, and a PON-side control unit configured to notify an OLT of, as power saving return information, a power holding time during occurrence of the power interruption of the ONU and a startup time, which is time until the transmitting and receiving unit returns from the power saving state, and, when the power-interruption detecting unit detects the power interruption, transmit a power interruption notification to the OLT. The OLT includes the PON control unit configured to determine, based on the power saving return information, whether the ONU can transmit the power interruption notification when the power interruption occurs in the power saving state.

Abstract: A timing interface module installs within a rack to increase bandwidth. The timing interface module receives a reference timing signal and outputs the reference timing signal to an optical multiplexer. The optical multiplexer also receives multiple data streams of different formats, and the optical multiplexer synchronizes the multiple data streams to the reference timing signal.

Abstract: An optical receiver includes: an interference unit generating a first interference light signal (ILS1) and a second interference light signal (ILS2) with an approximately inverse phase to that of the first interference light signal, by causing a received light signal to interfere with local oscillator light; a first interference light subtraction unit generating a first interference light subtraction signal (ILSS1) representing the difference between signals obtained by photoelectric conversion of ILS1 and a local oscillator light proportional signal having light intensity based on the light intensity of the local oscillator light; a second interference light subtraction unit generating a second interference light subtraction signal (ILSS2) representing the difference between a signal obtained by photoelectric conversion of ILS2 and the signal obtained by photoelectric conversion of the local oscillator light proportional signal; and a difference output unit outputting a signal representing the difference bet

Abstract: An optical transport network based on multimode/multicore fibers includes a mode-multiplexer to multiplex independent data streams from one or more transmitters; a multimode erbium-doped fiber amplifier (MM EDFA) to compensate for MMF loss; a multimode optical add-drop multiplexer (MM OADM) to add and/or drop multimode channels in multimode networks; a multimode optical cross-connect; and a mode-demultiplexer to separate various mode streams to one or more receivers.

Abstract: Automatic discovery and verification of optical communication links as well as isolation of link failures in an optical communication system.

Abstract: An antenna device is provided, which includes a first antenna unit and a second antenna unit. The first antenna unit includes a first radiation module, a power divider/combiner network connected to the first radiation module, and a feeder interface connected to the power divider/combiner network. The feeder interface is configured to connect to a radio remote unit (RRU) or a base station. The second antenna unit includes a second radiation module, a transceiver array connected to the second radiation module, a baseband processing unit (BPU) connected to the transceiver array, and an interface connected to the BPU. The interface of the second antenna unit is configured to connect to a baseband unit (BBU). Therefore, after the existing passive antenna is replaced by the provided antenna device, the RRU or base station in the original network can still be used, which reduces waste of resources.

Abstract: An automated test system for testing devices being manufactured comprises an infrared communications link for free space communications between a host and a device under test. The communications link is asymmetric and instructions from the host are acknowledged by the device. The instructions cause the device to operate, and the output of the device is monitored, logged, and compared to acceptance criteria. The host can then generate calibration messages to the device, to change the device operating characteristics as appropriate. The communications link uses an unmodulated data stream together with asynchronous handshaking and a robust checksum algorithm to ensure accurate communication.

Abstract: An optical adding and dropping device includes a drop section including an input port and having a through port and a plurality of drop ports set as output ports, a first multiplexer adapted to multiplex light from the through port and light from a plurality of add ports, and a spectrum foot removing section provided on the input side of the first multiplexer and adapted to remove a foot of a spectrum of light to be inputted from the add ports to the first multiplexer. The optical adding and dropping device can be configured at a low cost while it has adding and dropping functions.

Abstract: A radio-frequency (RF) remote control (10) has a user interface and transmits an RF signal (11) which designates a device (14) to be controlled and a command for that device. The RF signal is received by an intermediary device (12). The intermediary device, in turn, generates and broadcasts a plurality of high-power IR signals (13A-13F). These signals may be received directly by a controlled device (14A) or may be received indirectly by a controlled device (14B, 14C) after one or more reflections from objects (16A, 16B) and/or room surfaces (18). Thus, reliable control of the devices (14) is obtained even in situations where merely transmitting a typical IR signal may not provide reliable control of the device (14).

Abstract: An optical receiver, a method of operating an optical receiver, a correction based transimpedance amplifier circuit, and a method of adjusting an output of a transimpedance amplifier. In one embodiment, the optical receiver comprises an optical-to-electrical converter, a transimpedance amplifier, and a correction circuit. The optical-to-electrical converter is provided for receiving an optical signal and converting the optical signal to an electrical signal. The transimpedance amplifier is provided for receiving the electrical signal from the converter and for generating from the electrical signal an amplified electrical signal. The amplified electrical signal has inter symbol interference resulting from a reduced bandwidth of the transimpedance amplifier.

Abstract: A radio transmitter integrated circuit includes a photodiode array circuit, a digital conversion module, and a transmit baseband processing module. The photodiode array circuit converts received light into electrical image signals. The digital conversion module converts the electrical image signals into digital image signals. The transmit baseband processing module converts the digital image signals into digital transmit baseband or low IF signals.

Abstract: The systems and methods described herein provide a reconfigurable, long-range, optical modem-based underwater communication network. In particular, the network provides a low power, low cost, and easy to deploy underwater optical communication system capable of being operated at long distances. Optical modem-based communication offer high data rate, omni-directional spatial communication in the visual spectrum. The omni-directional aspect of communication is advantageous because precise alignment of communication units may not be required. The optical modems may be deployed via unmanned underwater vehicles (UUVs) and physically connected by tethers.

Abstract: Disclosed are universal QPSK transmitter structures and methods for generating different QPSK signals exhibiting different polarization schemes, namely PolMux, PolMod and PolSw. The bit rate of the generated signals is variable, thereby allowing the transmitter to adjust to varying network traffic conditions. Advantageously, the generated signals may be detected by analog receivers (PolSw-QPSK) and coherent receivers (PolMux-QPSK, PolMod-QPSK, and PolSw-QPSK).