Abstract: A method, apparatus, and program, for evaluating an optical network node. The method comprises providing at least one communication path of the node with a capability by which lasing can occur in the communication path, and detecting whether lasing has been established in the communication path to determine whether the optical node is operational. If no lasing is detected in the detecting, a fault exists in the communication path. The method further comprises determining an insertion loss in the communication path, and determining whether the insertion loss is comparable to a predetermined insertion loss, to confirm whether the node is configured correctly.

Abstract: An optical transceiver for converting and coupling an information-containing electrical signal with an optical fiber including a housing having an electrical connector with a plurality of XFI electrical interfaces for coupling with an external electrical cable or information system device and for transmitting and/or receiving an information-containing electrical signal having a data rate of at least 10 Gigabits per second on each interface, and a fiber optic connector adapted for coupling with an external optical fiber for transmitting and/or receiving an optical communications signal having a data rate at least 40 Gigabits per second; and at least one electro-optical subassembly in the housing for converting between an information-containing electrical signal and a modulated optical signal corresponding to the electrical signals.

Abstract: In a coherent optical receiver, a method of at least partially compensating Polarization Dependent Loss (PDL) of an optical signal received through an optical communications system. A respective multi-bit sample stream of each one of a pair of orthogonal received polarizations of the optical signal is tapped, and used to derive a respective metric value indicative of a quality of each multi-bit sample stream. A gain of an analog front end of the coherent optical receiver is adjusted based on the derived metric values.

Abstract: A fiber-optic communications interface (110) and method of operation that operates with a paired fiber-optic communications interface (112) in a redundant communications termination point (101). The fiber-optic communications interface (110) has a paired card interface (122) that exchanges at least a first subset of status data between a local bearer processor (124) and a paired bearer processor (144) located within a different card cage (112). The local bearer processor (124) processes bearer data channels communicating with a remote site (102) through a remote site fiber-optic line (106). A local data interface (128) exchanges data contained in the bearer data channels between the local bearer processor (124) and a local user data network (114). The local data interface (128) also exchanges at least a second subset of the status data with the paired bearer processor (144) through the local user data network (114).

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: A system operable to modulate a signal according to phase-shift keying (PSK) modulation includes one or more phase modulators that comprise one or more fractional phase modulators. A fractional phase modulator includes a splitter that splits a communication signal to yield a first communication signal with first amplitude and a second communication signal with second amplitude, where the ratio of the first and second amplitudes correspond to a phase shift. A phase shifter phase shifts the first or second communication signal. A first modulator modulates the first communication signal at a constant phase. A second modulator modulates the second communication signal at phases corresponding to the phase shift to encode data. A coupler couples the first communication signal and the second communication signal.

Abstract: An optical network transmission channel failover switching device is proposed, which is designed for use in conjunction with an optical network for providing a transmission channel failover switching function, which is characterized by the provision of a two-to-two (2×2) type of optical switch, a one-to-two (1×2) type of optical switch, and a monitoring beam generating module for providing a backup channel monitoring function that can be used to activate the switching action. This feature allows the utilization of the optical network system to have enhanced reliability, serviceability, and security.

Abstract: According to a WDM optical transmission system of the present invention, wavelength numbers information of a WDM signal light output from an upstream side optical amplifying unit to a transmission path fiber, and signal output level information thereof are transmitted to a downstream side optical amplifying unit utilizing a supervisory control light. In the downstream side optical amplifying unit, a loss (span loss) in the transmission path fiber is computed using the upstream side signal output level information and downstream side signal input level information, so that a gain to be set for a downstream side optical amplifier is calculated based on the computed loss, and also, the gain is corrected based on a difference between a target value of the signal output level computed using the wavelength numbers information and an actual measurement value thereof, so that the optical amplifier is controlled in accordance with the post-corrected gain.

Abstract: The invention relates to a tunable optical add/drop module (TOADM) monolithically integrated on a single planar lightwave circuit (PLC). The present invention overcomes the shortcomings of the prior art by providing virtual pupils at the interface between the channel waveguides and the slab waveguide on the PLC for focusing each wavelength channel, and additional on-chip lenses on the PLC for transforming the focal plane of the spatially dispersive demultiplexer into a substantially flat plane at the edge of the PLC. On-chip lenses are realized as reflective surfaces within slab waveguiding regions having a surface curvature to provide optical power.

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: According to one embodiment, an infrared signal decode circuit includes: a comparator; a correlation signal generator generating a sum of a first detection signal and a second detection signal as a correlation signal, the first detection signal being obtained by performing an absolute value calculation on a first correlation signal, the second detection signal being obtained by performing an absolute value calculation on a second correlation signal, the first correlation signal corresponding to a correlation between a binary signal and a first reference signal with a frequency substantially identical to a base frequency of a subcarrier of an infrared signal, the second correlation signal corresponding to a correlation between the binary signal and a second reference signal with a phase that differ from a phase of the first reference signal by 90 degrees; and a decoder binarizing the correlation signal generated by the correlation signal generator.

Abstract: In an optical transmission system by frequency-division multiplexing, the interference due to distortions of a first signal against a second signal can be reduced. In the optical transmission system where a modulated optical signal by the first signal is further modulated with the second signal for transmission, distortions of the first signal corresponding to a frequency band of the second signal is extracted. The extracted signal is phase-inverted and then adjusted in phase and amplitude with respect to the distortions of the first signal to obtain a correction signal. By intensity-modulating the first signal containing the distortions by the correction signal, the distortions of the first signal against the second signal can be cancelled out. Alternatively, by intensity-modulating the first signal containing the distortions by a combined signal of the correction signal and the second signal, the distortions of the first signal against the second signal can be cancelled out.

Abstract: A system operable to modulate a signal according to phase-shift keying (PSK) modulation includes a translator and a phase modulation system. The translator receives data signals and translates the data signals into control signals, where the number of control signals is greater than the number of data signals. The phase modulation system includes phase modulators. Each phase modulator receives a control signal and PSK modulates a communication signal according to the control signal.

Abstract: An optical access network system capable of transmitting and receiving high-speed signals and which allows the number of subscribers to be increased without increasing the number of wavelengths used is provided. An optical line terminal and an optical network unit are joined via an optical fiber transmitting line, a star coupler, and a plurality of branching optical fiber transmitting lines. The optical line terminal and optical network unit are constituted comprising an optical processing section and an electrical processing section. The optical processing section comprises a light-emitting element and a light-receiving element.

Abstract: Disclosed herein are a device and a method for an optical signal changeover that will not necessitate any addition to the capacity of the optical signal selection unit even when the N×M optical switches are expanded in scale, but can keep the optical signal selection unit compact in size and enhance the reliability of the unit. The optical signals received from plural optical transmission lines are converted into predetermined wavelengths by the wavelength conversion unit based on the settings given from the system monitoring control unit. The converted optical signals are bifurcated by the optical bifurcating unit and inputted to the optical switches of the active system and the optical switches of the stand-by system.

Abstract: A linear phase demodulator/down-converter comprises an optical amplitude modulator for modulating the amplitude of an optical input signal, a photo-detector, a loop filter and an optical phase modulator provided with a light source. The optical phase modulator/down-converter provides optical down conversion, optical up conversion, or a combination thereof. The photo-detector can be a balanced photo-detector. Linear phase demodulation and/or down conversion is performed completely in the optical domain.

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: Apparatuses, systems, and methods are disclosed that provide for an agile coherent optical modem that can generate agile RF waveforms and data rates on a generic opto-electronic hardware platform. An “agile coherent optical modem” [ACOM] approach to optical communications by employing a software configurable and adaptive technologies to the transport system. The ACOM generate agile RF waveforms and data rates on a generic opto-electronic hardware platform. By employing advanced communication techniques to the optical domain such as wavelength agility, waveform agility, and symbol rate agility, it is possible to enable robust optical communications. The ACOM allows for the transport capacity of a communications link to be varied, thereby accommodating variations in transport conditions, range, opacity, etc.

Abstract: The present invention provides systems and methods to adaptively control amplifier target power to maintain signal launching power as per design in networks with wavelength selective switch (WSS)-based reconfigurable optical add-drop multiplexers (ROADMs) using micro-electromechanical system (MEMS). Accordingly, signal OSNR does not collapse faster for WSS-based ROADMs than other similar configured system without WSS-based ROADM. In order to correct amplifier target power, the present invention utilizes system information about side-lobe size and OSNR at each amplifier. Related information, such as ASE level and size of side-lobes at each channel from upstream amplifiers, is passed to the network controller at each amplifier. Meanwhile, with target signal level and local WSS attenuation setting (given side-lobe size vs. WSS attenuation known) of each channel, the amplifier calculates what is total output power should be and adaptively maintains that power.

Abstract: A system for providing power to remote equipment where a transmit unit having lasers transmits laser light over optical fiber to a receive unit having photovoltaic receivers. The photovoltaic receivers convert the laser light to electrical energy for the remote equipment. The receive unit also sends a feedback signal to the transmit unit which the transmit unit uses to determine whether the lasers should be enabled for full power.