Abstract: A wireless communication interface for a portable wireless terminal and a system for wirelessly communicating by a portable wireless terminal with another device via a free space. The interface facilitates aligning the portable wireless device with another devices for improved communication. The interface including: a light source for generating a data-modulated visible light signal and outputting the visible light signal to the free space; an optical detector for generating an electrical signal by photoelectrically converting the visible light signal input from the free space, and for outputting the electrical signal. A demodulation unit demodulates the electrical signal input from the optical detector, and outputs a data signal.

Abstract: A storage area network extension, network and method include a storage terminal coupled to a remote node. The remote node is connected to a passive optical network (PON) for transferring data signals in the PON and storage signals to/from the storage terminal by employing subcarrier channels in the PON to enable concurrent bidirectional transfer of the data and the storage signals. A storage area network is coupled to the storage terminal and configured to store and retrieve the storage signals for transfer over the PON.

Abstract: A testing input module for testing an in-service WDM system is provided. The testing input module includes a first light source configured to emit a first light signal to one or more empty channels of the in-service WDM system; and a tunable second light source configured to emit a second light signal to test the one or more empty channels. The testing input module also includes a first switch module configured to: receive from the first light source and output the first light signal during a first time interval; and receive from the second light source and output the second light signal during a second time interval. The second time interval is a duration wherein a channel power monitoring function of the in-service WDM system is not triggered.

Abstract: An apparatus for detecting wavelength drift and a system and method for locking wavelengths are disclosed herein so that multiple optical modules can share a wavelength locking apparatus without any wavelength selecting module. The output signals of only one optical module are scrambled at a time, and the identifier information carried in the optical signals output by different optical modules is the same, for example, the same frequency is applied to scrambling of every optical signal. Therefore, the scrambling apparatus is simplified, and the interference between scrambling signals is eliminated. Because no mechanical or electrical apparatus is used for controlling the wavelength switching, the cost is reduced, the locking speed is increased, the accuracy of signal processing is improved, and the precision of wavelength locking is enhanced.

Abstract: Methods and apparatus for efficiently utilizing an optical control plane distinct from an electronic control plane to facilitate the setup of paths in a dense wave division multiplexing network are disclosed. According to one aspect of the present invention, a method includes receiving a probe arranged determine the optical feasibility of a first path, and determining a probability of success associated with the probe. The probability of success indicates a likelihood that the probe will be successfully routed on the first path to the destination, and is associated with a particular wavelength. A second path on which to route the probe is dynamically identified if the probability indicates a low likelihood of successful routing on the first path. Finally, the method includes determining if a notification associated with the probe has been received, and altering the probability of success based on the notification if the notification has been received.

Abstract: It is an object of the present invention to provide an FSK demodulator which can be used in the optical information and telecommunications and the like, and which can appropriately demodulate an FSK signal by compensating a delay of an optical FSK modulated signal due to dispersion and the like of an optical fiber. The above-mentioned problem is solved by a frequency shift keying (FSK) demodulator (1) composed of a branching filter (2) for branching an optical signal according to wavelengths thereof; a delay adjusting apparatus (3) for adjusting a delay time of two lights branched by the branching filter; a first photodetector (4) for detecting one optical signal branched by the branching filter; a second photodetector (5) for detecting a remaining optical signal branched by the branching filter; and a means (6) for calculating a difference between an output signal of the first photodetector and an output signal of the second photodetector.

Abstract: An optical transmission apparatus includes a first transceiver unit coupled to a first node, a second transceiver unit coupled to a second node, an electrical signal processing unit provided between the transceiver units, a first transmission clock generating unit configured to generate a clock used by the second transceiver unit based on a clock of a signal arriving through the first node, a second transmission clock generating unit configured to generate a clock used by the first transceiver unit based on a clock of a signal arriving through the second node, a selector configured to select an output clock of the first transmission clock generating unit at a time of optical input interruption at the second node, and a frequency dividing unit configured to produce a frequency-divided clock obtained by dividing frequency of the output clock selected by the selector for provision to the second transmission clock generating unit.

Abstract: In a method and device which can quickly detect a fiber misconnection without setting an expected value, a node identifier of source node and an identifier of an interface for inputting/outputting a signal are set in a predetermined first field of a header to be transmitted to a destination node, and when both identifiers set in the first field are received from the destination node, both identifiers are set in a predetermined second field of the header to be transmitted and stored with the first field. When the identifiers set in the first and second fields are received and the identifiers of the second field among the identifiers are consistent with the identifiers of the first field stored at the second step (means), a connection is determined to be correct.

Abstract: A system is provided for intercepting signals transmitted between a target served by a fiber optic network and a subscriber. A network is described having a phone switch at a central office configured to receive signals for transmission to and from a target, such as the target of a criminal investigation. A signal received at the central office is assigned to an analog circuit, and a monitoring device configured to intercept and monitor the signal is installed along the analog circuit at a location that allows the monitoring of communications without notifying the target that he is under surveillance. After the signal has been monitored, it is converted to a digital signal for transmission. A method is also provided for intercepting a signal transmitted between the target served by a fiber optic network and a subscriber, such that a monitoring device may be installed without alerting the target.

Abstract: A new transmission link configuration with remote Er post- and pre-amplifiers where pump power is shared between a pair of fibers carrying traffic in opposite directions is proposed. A budget increase of >4 dB is demonstrated.

Abstract: An optical transmitting circuit (2) modulates multimode oscillation light using an information signal, subjects at least one oscillation-mode light beam of the multimode oscillation light to a predetermined operation, and outputting the result to an optical transmission channel. An optical receiving circuit (8) receives an optical signal transmitted through the optical transmission channel, subjects the received optical signal to an operation reverse to the predetermined operation to recover an optical signal as it was before being subjected to the predetermined operation, and converting the recovered optical signal into an electrical signal, thereby reproducing the information signal.

Abstract: According to one embodiment, an optical receiver adapted to recover OOK or PAM data carried by a modulated optical carrier has an optical detector adapted to produce a sequence of vector pairs having first and second digital vectors indicative of complex values of first and second polarization components, respectively, of the modulated optical carrier at a corresponding sampling time. The optical receiver also has a digital processor that is connected to receive the sequence and is adapted to perform a rotation on each pair in a manner that tends to compensate for polarization rotation produced by transmitting the modulated optical carrier from an optical transmitter thereof to the optical receiver. The digital processor is further adapted to estimate values of the OOK or PAM data encoded onto each of the first and second polarization components based on the vectors produced by the rotation in a manner responsive to values of energy errors in the estimated values.

Abstract: In a coherent optical receiver, a light intensity value of signal light providing an optimum reception state is determined when ideal signal light free from waveform distortion is used as the signal light in a state where local-oscillator light is turned on. A first amplitude value of an analog electrical signal corresponding to the signal light is stored in a storage section, wherein the first amplitude value is obtained at a time when the ideal signal light of the light intensity value determined is used as the signal light in a state where the local-oscillator light is turned off. Light intensity of the signal light is determined so as to make a second amplitude value equal to the first amplitude value, wherein the second amplitude value is an amplitude value of the analog electrical signal which is obtained at a time when actual signal light is used as the signal light in a state where the local-oscillator light is turned off.

Abstract: A method for determining symbols PSK modulated on an optical carrier includes interfering a first polarization component of the modulated optical carrier and a reference optical carrier in a first optical mixer and interfering the first polarization component of the modulated optical carrier and the reference with a different relative phase in a second optical mixer. The method also includes sampling the interfered carriers from the first optical mixer to produce first digital sampled values and sampling the interfered carriers from the second optical mixer to produce second digital sampled values. The first and second digital sampled values of a sampling period form a first complex sampling value thereof. The method also includes offsetting a phase of a complex signal value corresponding to each first complex sampling value to correct for a phase error caused by a frequency offset between the modulated and reference optical carriers.

Abstract: A QKD system (10) having two QKD stations (Alice and Bob) optically coupled by an optical fiber link (FL), wherein Bob includes a variable timing delay arranged between Bob's controller (CB) and modulator (MB) or detector unit (40). A set-up and calibration procedure is performed wherein delay DL2 is adjusted until the timings for the modulator and detector unit (TSB and TS42, respectively) are established. Delay DL2 is then fixed so that the detector unit and modulator operate in a common timing mode that is not changed if the synchronization signal is changed. The timing TSS of the synchronization (sync) signals (SS) sent from Alice to Bob is adjusted to arrive at optimum system performance. Once the QKD system is in operation, because the sync signal can drift, the sync signal timing TSS is dithered maintain optimum QKD system performance.

Abstract: An optical transmitter which modulates the phases and intensities of double pulses and then transmits them, includes a branching section which branches each of the input double pulses to first and second paths, a first optical modulator placed in the first path, second and third optical modulators placed in series in the second path, and a combining section which combines the double pulses having traveled through the first path with the double pulses having traveled through the second path to output double pulses. A control section controls such that each of the first and second optical modulators performs any one of relative intensity modulation and relative phase modulation on the double pulses passing through, and the third optical modulator performs relative phase modulation on the double pulses passing through.

Abstract: A digital camera 800 receives from lighting units 120a-120l lights temporarily changing in luminance and produces a coordinates data list 8031 of the lighting units. Decoding unit 804 reads change in luminance at each luminance-point coordinates of the lighting unit to decode information. It is judged based on the decoded information of a data format 900, whether plural luminance-point coordinates having the same guidance point ID information 902 are found. When the plural luminance-point coordinates having the same guidance point ID information are found, a location of the plural luminance-point coordinates is analyzed to draw and display a circumscribed polygon having its vertices at these coordinates on a through image in an overlapping manner. A hatched area is set inside the circumscribed polygon and the decoded information is displayed within the hatched area.

Abstract: A transmitter for an optical RZ-DPSK communication signal comprises a source for an optical carrier, an electro-optical modulator which comprises at least one element having an optical path length adapted to be varied by an electrical driver signal for intensity modulating the optical carrier based on the driver signal, and a driver circuit for generating the driver signal from an electrical communication signal. The driver signal is an impulse-type signal having two types of impulses spaced in time by a neutral signal state, wherein in the presence of the neutral state of the driver signal at the modulator, the transmission of the modulator becomes zero, and the two types of impulses each cause a transmission different from zero and a phase which is specific for the type of the impulses in the modulator.

Abstract: Methods and apparatus for implementing synchronous Optical Time Division Multiplexing are presented. Namely, a method of upconverting and combining N input NRZ optical data signals, each having an approximately equal pulse width and period, into one time-division multiplexed output signal, as well as a method for the inverse, i.e., down converting the N demultiplexed component signals are presented. Apparatus to implement these functionalities is also presented.

Abstract: A bridge controller, which controls relay between terminals including emission units and addresses assigned to the terminals, acquires coordinates of a light-received element in an light receiving unit at which light emitted from an emission unit is received, and stores the acquired coordinates in a location information table memory in association with a logical location on the network. Thereafter, it is determined whether or not the stored coordinates differ from newly acquired coordinates. When it is determined that the stored coordinates differ from the newly acquired coordinates, the logical location associated with the coordinates stored in the storage unit is controlled to be changed and stored.