Abstract: The current options for wireless communication have changed the way people work and the way in which networks can be deployed. However, there remains unresolved problems in the setup and configuration of wireless communication links. Both known cellular and ad hoc wireless networking protocols and systems are deficient in that the ability for users to communicate without a priori knowledge of MAC addresses (represented by phone numbers, IP addresses and the like) is limited or may be compromised in a hostile environment. In contrast, provided by aspects of the present invention are devices, systems and methods for establishing ad hoc wireless communication between users that do not necessarily have MAC addresses and the like for one another. In some embodiments, a first user visually selects a second user and points a coherent light beam at an electronic device employed by the second user.

Abstract: In order to enhance dispersion control, the apparatus includes a dispersion controller; a quality index generator generating a quality index representing a quality of an optical signal output from the dispersion controller; and a searching unit searching for an amount of dispersion control applying to the dispersion controller which amount optimizes the quality index, wherein the searching unit includes a splitting-half searching unit roughly searching, in a splitting half method, a range in which dispersion is controllable by the dispersion controller for an amount of dispersion control such that the quality index generated by the quality index generator becomes preferable, and a sweep searching unit thoroughly searching, by sweeping, a limited range based on the amount of dispersion searched by the splitting-half searching unit for an amount of dispersion control that optimizes the quality index generated by the quality index generator.

Abstract: An optical wavelength controlling method and a system thereof for an optical wavelength division multiplexing transmission system, wherein a plurality of wavelengths of channels are multiplexed and transmitted by an optical transmitting unit, and the multiplexed wavelengths are divided into the wavelengths of the channels by an optical receiving unit, are disclosed. The optical wavelength controlling method includes: a step of reducing optical power of the wavelength of a target channel, and transmitting the wavelengths; a step of evaluating channel crosstalk based on a code error rate of a channel adjacent to the target channel, and detecting a shift of the wavelength of the target channel; and a step of compensating for the shift of the wavelength of the target channel.

Abstract: A bias-control circuit that provides operating point control for a Mach-Zehnder modulator experiencing optical absorption at their interferometric arms. The bias control circuit generates compensation signals that are used to counter the thermally induced index shifts as a result of absorption. In addition, an operating point with desirable transmitter characteristics can also be arbitrarily chosen by over-compensating or under-compensating thermal effects.

Abstract: A calculation processing unit controls temperature of a Peltier device based on a slope of a waveform obtained by subtracting a waveform of a B-arm monitoring signal from a waveform of an A-arm monitoring signal and a value obtained by subtracting a value B of the B-arm monitoring signal from a value A of the A-arm monitoring signal. Similarly, the calculation processing unit controls a phase of the A-arm and a phase of the B-arm. An A-arm side micro-controller controls temperature of an A-arm side heater 22 based on the value of the A-arm monitoring signal, and controls the phase of the A-arm. A B-arm side micro-controller controls temperature of a B-arm side heater based on the value B of the B-arm monitoring signal, and controls the phase of the B-arm.

Abstract: Adaptive transmission of optical signals. A dynamically adaptive optical receiver can include a receive optical subassembly (ROSA). The ROSA can include an opto-electronic transducer configured to receive an incoming optical signal from an incoming optical transmission link, circuitry for evaluating one or more properties related to the incoming optical signal, logic for comparing the one or more properties of the incoming optical signal to stored information representing threshold values, and circuitry for controlling a transmission characteristic of an outgoing optical signal based on a result of the comparison.

Abstract: A multimode optical fibre communications system, and in particular to a system in which non-linearities in the propagation of the signal through a multimode optical communications channel degrade the signal presented to the receiver. The system includes an optical transmitter unit for connection to a multimode optical fibre transmission link. The transmitter unit has a data input for receiving an input data signal, a data signal processing circuit and a source of optical radiation. The data signal processing circuit is arranged to receive the input data signal from the data input and to provide a processed data signal to the source of optical radiation and the source of optical radiation is arranged to generate from this an optical signal for transmission by a multimode optical fibre.

Abstract: Branches are grouped into a group 1 including first and second branches, and a group 2 including third and fourth branches. The signal after being passed through a dual pin photodiode in one branch included in the group 1 and being at the earlier stage of a CDR circuit is obtained. Also, from the later stage of the CDR circuit in the other branch in the group 1 is obtained. The obtained signals are passed through low pass filters, and an average value over a plurality of symbols is obtained. The signal from the earlier stage of the CDR circuit is multiplied by the signal from the later stage, and they are averaged. The obtained value reflects the phase difference of the two delay interferometers in the group 1. The group 2 is monitored by using the same method.

Abstract: Techniques are disclosed for providing bi-directional data services involving a plurality of wavelengths. The data services may be hybrid in nature, including both digital and analog data signals. The techniques may be implemented, for instance, in an optical module, and allow one or more wavelengths to pass-through while other wavelengths are terminated or otherwise diverted. In one example embodiment, the techniques are embodied in a quad-port optical module having two input/output (I/O) ports and pass-through capability for at least one of the wavelengths, add capability for at least one wavelength, and drop capability for at least one wavelength. The module may further include transmit and/or receive capability for one or more signal types. The module can be operatively coupled with a bidi device or other suitable transceiver, to provide modular transmit-receive capability for a desired signal type.

Abstract: A signal transmission system in accordance with the invention is implemented using a dual-purpose pin of an optical sub-assembly. The dual-purpose pin is used to propagate an analog signal out of the optical sub-assembly and also for providing an access point where an external element may be coupled to the optical sub-assembly for modulating the analog signal. The optical sub-assembly houses a photodetector, a signal transmitter circuit, and a signal receiver circuit. The photodetector receives light and generates a corresponding electrical signal indicative of the light intensity. The signal transmitter circuit converts the electrical signal received from the photodetector into the analog signal that is transmitted out of the dual-purpose pin. The signal receiver circuit located inside the optical sub-assembly is configured to monitor the modulated analog signal from the dual-purpose pin and generate therefrom, a control signal inside the optical sub-assembly.

Abstract: The invention relates to a method for optimizing the optical power in an optical network that has a plurality of network nodes each having a transmitter and a receiver. The method comprising generating an optical signal at a first network node, receiving the optical signal at a second network node, detecting the optical power of the optical signal at the second network node, determining whether the optical power detected is outside a defined range, and in this case, generating, for the first network node, a control signal for increasing or decreasing the optical power, sending the control signal to the first network node, and increasing or decreasing the optical power of the optical signal emitted at the first network node. The invention further relates to an optical network having network nodes which are operable to implement this method.

Abstract: The present invention includes a fast algorithm to compute the pre-equalized waveform for simultaneous compensation of the self-phase modulation and chromatic dispersion experienced by a high-speed optical signal, e.g., at 10 Gb/s, and shows that it is used for an automatic self-adapting pre-equalization when the knowledge on transmission link details is inaccurate or incomplete.

Abstract: An array of light beam emitter sections comprises: a substrate having a surface divided into an array of sections; and a grouping of light emitters disposed at each surface section and configured to emit light beams at different emission angles with respect to the surface. Also disclosed is apparatus for establishing optical communication channels between the array of light beam emitter sections and an array of light detectors. The apparatus comprises a controller coupled to the arrays of emitter sections and detectors for mapping at least one light emitter of each grouping with a light detector of the detector array to establish optical communication channels between the arrays based on the mappings.

Abstract: A low-cost configuration of, and at the same time to control the variable dispersion compensator at a high speed in a variable dispersion compensator for compensating the wavelength dependent accumulated dispersion resulting from the wavelength dependency of the transmission fiber and fixed dispersion compensator in a long-distance high-speed WDM transmission system. In order to achieve the object mentioned above, the wavelength dependent representative characteristic of the transmission fibers 4-1 . . . n, and the wavelength dependent representative characteristic of the DCFs 13-1 . . . n are recorded and maintained in advance in the dispersion control circuit 5-1 . . .

Abstract: A method of operating an optical transmission system is described. The transmission system is provided with a bit-to-bit polarization interleaved bitstream having a given bitrate. The transmission system comprises a birefringent element and/or a decision circuit. The birefringent element and/or the decision circuit are triggered by a trigger signal having a frequency of half of the bitrate.

Abstract: There is provided an opto-electronic communication system. The opto-electronic communication system has (a) a transmitter module including an electro-optical source for converting an electrical input signal into an optical output signal, (b) a receiver module including an opto-electrical detector for converting an optical input signal into an electrical output signal, (c) a sensor for sensing a bit rate of the optical input signal, (d) an adaptation unit associated with the transmitter module for varying an operation parameter of the transmitter module, and (e) a processing unit for determining a desired operating parameter of the transmitter module based on the bit rate, and for controlling operation of the adaptation unit in order to adapt operation of the transmitter module in accordance with the desired operating parameter.

Abstract: A method for receiving an optical signal is included where an ingress signal is split into a first portion and a second portion. A relative delay is induced between the first portion and the second portion, which are optically interfered to generate at least one interfered signal. Quality criteria of a monitored signal at least based on the at least one interfered signal is monitored so that a relative delay based in the quality criteria may be adjusted.

Abstract: In a cryptographic key distribution system by the phase modulation using a single photon state or a faint LD light, there is required an interferometer independent on polarization and stabilized against thermal fluctuations in order to make a transmission distance longer. Cryptographic key distribution systems are generally low in cryptographic-key-generating efficiency, and an improvement in the efficiency is demanded. In the present invention, two interferometers are disposed within the receiver so as to require no phase modulator within the receiver, thereby achieving a polarization-independent receiver. The pulses are paired, and the signal is transmitted with the relative phase, and the interval of the paired pulses is sufficiently reduced to set the optical path within the interferometer in the receiver to be smaller, thereby achieving the interferometer stabilized against thermal fluctuations.

Abstract: The invention relates to a method for determining and/or evaluating a differential, optical signal. According to the invention, at least two first light sources (S1, S2) which are sequentially clocked in terms of light and emitted in a phased manner are provided, in addition to at least one receiver (E) which is used to receive at least the alternating light portion arising from the first light sources (S1, S2). The light intensity radiating through at least one light source (S1, S2) in the measuring arrangement is controlled in such a manner that the clock synchronous alternating light portion, which occurs between different phases, is zero in the receiver (E). By determining the reception signal in the receiver (E) in relation to the phase position in order to regulate the radiated light intensity and by producing an adjustable variable (R) directly or by adding current in the receiver, it is possible to simplify digital implementation of the method with as little sensitivity loss as possible.

Abstract: Disclosed are systems and methods for improving communication in an optical communication system having spectrally shaped pulses. Embodiments of the systems and methods include sending a first spectrally shaped pulse over a channel connecting a transmitter and a receiver. Then, comparing the spectrally shaped pulse received at the receiver to a predetermined spectrally shaped pulse. The systems and methods further include obtaining a preemphasis coefficient that describes the difference between the spectrally shaped pulse received at the receiver to the predetermined spectrally shaped pulse by utilizing a mathematical description of C(?k)ej(??(?k)) and multiplying a second spectrally shaped pulse with the preemphasis coefficient before sending the second spectrally shaped pulse to the receiver.

Abstract: An integrated optoelectronic module and optical fiber for coupling a pair of information system devices having an electrical input/output interface using optical signal communication including an optical fiber; a housing on at least one end of the optical fiber including an electrical connector for coupling with one of said information system devices; an electro-optic subassembly disposed in the housing for coupling to the information system device integrally coupled and attached to the optical fiber for transmitting an optical signal over the fiber; a circuit disposed in the housing for detecting the power of the received optical signal; and a communications interface for communicating the received power level to allow setting of the remove optics transmitter.

Abstract: A transmitter-receiver having a means for automatically determining the status of transmission medium such as optical fiber, and a means for automatically setting and resetting the transmission rate and/or output power according to the status of the transmission medium, a transmission loss and gain measurement method, and a transmitting-receiving system. A transmitter-receiver comprises at least: an output power controller for controlling the output power of a transmitter; an input power measuring section for measuring the strength of input signals; and an information processor for deriving the loss or gain of a path to change the output power of the transmitter and/or the rate of data transmission according to the derived loss or gain of the path.

Abstract: A method is disclosed for monitoring and controlling the bit error rate (BER) in an optical communication network where an optical receiver in the optical transmission network. The method includes the steps of decombining a combined channel signal received from the network and then monitoring a real time bit error rate (BER) of a decombined channel signal. The determined BER is then communicated, such as through an optical service channel (OSC) to an optical transmitter source that is the source of origin of the channel signal. Based upon the determined BER, the chirp of a channel signal modulator at the optical transmitter source that generated the monitored channel signal is adjusted by, for example, adjusting its bias. The same channel signal received at the optical receiver can be monitored again to determine if an acceptable level for the BER has been achieved by the previous chirp adjustment.

Abstract: An apparatus and method for transmitting a signal for optical network applications with automatic chromatic dispersion compensation. The apparatus includes a first optical transmitter. The first optical transmitter includes a first light source configured to generate a first laser signal in response to a first laser drive signal, a first data modulator configured to receive the first laser signal and a first data drive signal and output a first chirped return-to-zero signal, and a first signal source configured to generate a first non-return-to-zero signal. Additionally, the apparatus includes a first clock and data recovery system, a first data driver, a first adjustment system, and a first control system.

Abstract: A transmitter (11) emits a single wavelength optical signal and transmits this as a wavelength channel (13) in a compound multiplex signal through the WDM network. The receiver (12) selects the single wavelength optical signal (21) from the compound multiplex signal using a band-pass filter. A wavelength fit detector (15) determines a feedback signal by correlating variations of the amplitude of the received signal with variations of the traffic density. This feedback signal is then returned to the transmitter (11) via a back channel (16) and serves to tune the wavelength of the single wavelength optical signal.

Abstract: An optical receiver includes a first light receiving element to convert an optical signal to an electric signal and to output the electric signal from one end. A light receiving element row is connected to the other end of the first light receiving element to supply electric power to the first light receiving element. The light receiving element row includes a plurality of second light receiving elements connected in series.

Abstract: The invention relates to clock recovery in optical communication systems. Optical clock frequencies are recovered from a plurality of optical channels by using a single optical resonator. The optical resonator is matched with the carrier frequencies and the sideband frequencies of the data signals sent at different channels. The separation range of the optical resonator is selected such that the clock frequency of at least one data signal is substantially equal to the separation range of the optical resonator multiplied by an integer greater than or equal to two. The method according to the invention allows the use of different clock frequencies at different optical channels. Furthermore, the method provides considerable freedom to select the spectral positions of the optical channels.

Abstract: The present invention includes apparatus and method of a variable step size dithering control algorithm for polarization mode dispersion controllers (PMDCs). The dithering step size of the PCs is adjusted according to the feedback signal including degree of polarization (DOP).

Abstract: In a communication system comprising first and second nodes, a multilevel amplitude modulated signaling technique is utilized. The first and second nodes may communicate over a Fibre Channel link or other medium. The first and second nodes comprise respective transmitter and receiver pairs, with the transmitter of the first node configured for communication with the receiver of the second node and the receiver of the first node configured for communication with the transmitter of the second node. The first node is configured to generate a signal for transmission over a serial data channel to the second node, the signal having a multilevel amplitude modulated format in which, within a given clock cycle of the signal, multiple bits are represented by a given signal level.

Abstract: An optical receiving apparatus sets, efficiently and optimally, a delay interferometer and a variable wavelength dispersion compensator in the apparatus.

Abstract: Methods and apparatuses are provided for performing jitter measurements in a transceiver module. Accordingly, there is no need to use expensive test equipment that must be inserted into and removed from the network in order to obtain these measurements. In addition, because the measurements can be obtained at any time without any interruption in communications over the network, jitter performance can be monitored more closely and more frequently to facilitate better and earlier diagnosis of problems that can lead to failures in the network.

Abstract: A multiplexer of a transmission section generates a clock signal by multiplying a reference clock signal of a digital image signal by a predetermined number ‘K’. A parallel digital image signal is converted into a serial digital signal on the basis of the clock signal, and the serial digital signal is converted into an optical signal in an optical transmission section for transmitting. A demultiplexer extracts a reception clock signal from a serial digital reception signal which is converted into an electric signal in an optical reception section of a reception section, the serial digital reception signal is converted into a parallel signal and a signal corresponding to the parallel digital image signal on the basis of the reception clock signal, and a clock signal corresponding to the reference clock signal is recovered by multiplying the reception clock signal by ‘1/K’.

Abstract: An optical transmission system having optical transmit and receive filters having passbands adjusted or selected for opposite and equal wavelength offsets from the optical wavelength of a carrier or the channel center wavelength.

Abstract: An optical network terminal, which includes an optical transmitter, monitors the status of the optical transmitter, such as the output or the power consumption of the optical transmitter, to determine when the optical transmitter is illegally transmitting. When an illegal transmission is detected, the optical network terminal removes power from the optical transmitter.

Abstract: A passive optical network includes an optical line termination for generating multiple downward optical signals and multiple optical network units for receiving the downward optical signals. Each optical network unit includes a receiver for converting a corresponding downward optical signal inputted from the optical line termination into a first voltage signal and outputting the first voltage signal. Additionally, each optical network unit includes a transmitter for calculating a distance to the optical line termination from an intensity of the first voltage signal outputted from the receiver and generating an upward optical signal having an intensity adjusted according to the calculated distance to the optical line termination.

Abstract: A transmission apparatus that receives an optical signal by selecting any one of a plurality of provided optical signal transmission paths through protection control is configured to include a plurality of optical signal outputting sections that output the optical signals transmitted through said optical signal transmission paths respectively as optical signals having wavelengths that are different from each other, a wavelength selective optical switch capable of selectively outputting light of a wavelength corresponding to any one of the optical signals coming from the optical signal outputting sections on the basis of the frequency of a controlling frequency signal, and an optical switch controlling section that supplies said controlling frequency signal to the wavelength selective optical switch so as to output the optical signal coming from the optical signal transmission path side that is selected by said protection control among the optical signals coming from the optical signal outputting sections.

Abstract: The optical line terminal has a PON transceiver including an error correction code decoder. The error correction decoder includes: a shortening compensation parameter table; and a syndrome calculator for calculating a syndrome by referring to the shortening compensation parameter table, or an error search part for calculating an error position or an error value by referring to the shortening compensation parameter table. Also the optical network terminal has a PON transceiver including an error correction code decoder. The error code decoder includes: a shortening compensation parameter table; and a syndrome calculator for calculating a syndrome by referring to the shortening compensation parameter table, or an error search part for calculating an error position or an error value by referring to the shortening compensation parameter table.

Abstract: The present photonic RF generation and distribution system provides a system and method for distributing an RF output signal. The photonic RF distribution system includes two optical sources for generating optical signals. A first optical source (42) is operable to generate a first optical signal having an operating frequency. A second optical source (44) is operable to generate a second optical signal having an operating frequency. A modulator (46) is operable to impress an RF modulation signal on a tapped portion of the first optical signal such that a modulated signal is generated. A first coupler (52) combines the modulated signal with a tapped portion of the second optical signal, thereby forming a combined signal having a difference frequency component. A control photodetector (50) is responsive to the combined signal to generate a tone signal.

Abstract: An optical transmission equipment in an optical communication system interconnecting two optical transmission equipment sets by a main transmission line and a backup transmission line. An optical amplifier amplifies and outputs optical signals from one transmission line in use, interconnecting the optical transmission equipment concerned with neighboring upstream optical transmission equipment, and outputs the optical signals including a signal component and a noise component. A controller controls an optical signal level so that a signal component in the optical signal reaches a predetermined level.

Abstract: The inventors propose herein a switch fabric architecture that allows broadcasting and fast channel access in the ns-range. In various embodiments of the present invention, 10 Gb/s receiver modules are based on a novel heterodyne receiver and detection technique, which is tolerant to moderate wavelength drifts of a local oscillator. A gain clipped electrical amplifier is used in the novel receiver as a rectifier for bandpass signal recovery.

Abstract: The discrimination phase margin monitor circuit (10) of the present invention comprises a first discrimination circuit (11 and 12) discriminating an input data signal using a clock signal extracted from the input data signal, a second discrimination circuit (13 and 14) discriminating the input data signal using a clock signal with a frequency different from that of the clock and an operation circuit (15 and 16) calculating the exclusive OR of the output signal of the first discrimination circuit and that of the second discrimination circuit and obtaining a phase margin monitor output signal by averaging the exclusive ORs.

Abstract: In an optical signal monitoring method in wavelength multiplexing and an optical network, an area corresponding to a characteristic pattern of an eye pattern of an optical signal to be monitored, which characterizes a deterioration, is extracted from a database storing a map which associates a quality deterioration factor and deterioration amount of the optical signal with the characteristic pattern of the area of the eye pattern of the optical signal. The extracted pattern is collated with the map stored in the database to monitor the quality deterioration factor and deterioration amount of the optical signal, an occurrence time of a deterioration, duration of a deterioration, a deterioration occurrence cycle, and a deterioration duration cycle. An optical signal monitoring apparatus is also disclosed.

Abstract: An optical signal transmission apparatus for transmitting a plurality of data signals comprising a plurality of inputs for receiving a respective one of the data signals and delivering the respective data signal with a controlled phase and at a controlled data rate. A plurality of optical carrier signals having different wavelength is generated. Each of a plurality of first modulators is operative for modulating a respective one of the optical carriers with a respective data signal to provide a first-modulated optical carrier signal. An optical signal-routing device has a plurality of input ports, each port being for receiving a respective one of the first-modulated optical carrier signals and delivering it to the output port of the device.

Abstract: An optical dispersion monitoring apparatus and an optical dispersion monitoring method are capable of monitoring dispersion accurately with a simple construction in an optical transmission system using the same. To this end, the optical dispersion monitoring apparatus includes a light receiving section converting an input optical signal into an electrical signal, a signal transition position detecting section detecting the voltage level of a waveform of the output signal from the light receiving section, at a crossing point of a rising edge and a falling edge, and a cumulative dispersion information extracting section comparing the voltage level at the crossing point with a reference signal to extracts cumulative dispersion information.

Abstract: An apparatus and method for controlling an optical interferometer are provided. The method includes setting a thermoelectric cooler (TEC) temperature of the optical interferometer to a room temperature, obtaining an optimal temperature using a difference between two output powers of the optical interferometer based on eye opening of the two output powers and applying an optimal heat voltage generating the optimal temperature to a delay adjuster of the optical interferometer, and performing dithering at the optimal temperature to stabilize the optimal heat voltage.

Abstract: An optical transmission system including an optical transmitting device and an optical receiving device. The optical transmitting device includes a data signal splitting section for splitting data signal information into at least two parts and generating at least two electrical signals having different center frequencies and bands, a frequency multiplexing section for performing frequency multiplexing for the at least two electrical signals, and an electrical-to-optical conversion section for converting the frequency-multiplexed signal to an optical signal and sending it to an optical transmission path. The optical receiving device includes an optical-to-electrical conversion section for converting the optical signal to a frequency-multiplexed signal, a band demultiplexing section for demultiplexing the frequency-multiplexed signal to obtain at least two electrical signals, and a data signal recovering section for recovering the data signal based on the at least two demultiplexed electrical signals.

Abstract: In an optical transmitting or receiving apparatus, a plurality of replaceable electro-optic converters or a plurality of replaceable opto-electric converters are provided in correspondence with optical transmission lines.

Abstract: The memory of the optical line terminal (OLT) of a broadband passive optical network (BPON) is increased to store, in addition to an active identity number, such as the serial number, of the current optical network terminal (ONT) connected to a network end point, a standby identity number, such as the serial number, of a replacement optical network terminal (ONT) when upgrades are requested by the end users, or partial or total failures are reported by the end users.

Abstract: An optical receiver includes a first light receiving element to convert an optical signal to an electric signal and to output the electric signal from one end. A light receiving element row is connected to the other end of the first light receiving element to supply electric power to the first light receiving element. The light receiving element row includes a plurality of second light receiving elements connected in series.

Abstract: An optical receiver photonic integrated circuit (RxFIC) comprises a semiconductor monolithic chip having an input to receive from an optical transmissior link a combined channel signal originating from an optical transmitter source and comprising a plurality of channel signals having different wavelengths forming a wavelength grid. An optical decorobiner is integrated in the chip and optically coupled to the input to receive the multiplexed channel signal and provide a decombined individual channel signal on an output waveguide of a plurality of such output waveguides provided from the optical decombiner. A plurality of photodetectors are also integrated in the chip and each photodetector is optically coupled to one of the output waveguides to receive a decombined channel signal and convert the channel signal to an electrical signal.