Fujitsu Corporation

Fujitsu Network Communications, Inc.

Cechan Tian

Susumu Kinoshita

Takao Naito

Koji Takeguchi

Satoru Odate

Olga I Vassilieva

Yasuhiko Aoki

Remi Pecqueur

Joseph R Rodriguez

Ashwin Anil Gumaste

Ching-Fong Su

A demodulator comprises an input splitter, optical device sets, and couplers. The input splitter splits an input signal comprising symbols to yield a number of signals. A first optical device set directs a signal of along a first path. A second optical device set directs another signal along a second path to yield a delayed signal. At least a portion of the second path is in free space. A path length difference between the first path and the second path introduces a delay between the first signal and the second signal. A coupler receives a portion of the signal and a portion of the delayed signal to generate interference, where the interference indicates a phase shift between a phase corresponding to a symbol and a successive phase corresponding to a successive symbol.

Free-space DQPSK demodulator

A flexible open ring optical network includes a plurality of nodes connected by twin or other suitable optical rings. Each node is operable to passively add and passively drop traffic from the rings. The nodes may include a transport element for each ring. The transport elements include an optical splitter element and an optical combiner element. The optical splitter element is operable to passively combine an add signal including local add traffic and a first transport signal including ingress traffic from a coupled optical ring to generate a second transport signal including egress traffic for transmission on the coupled optical ring. The optical combiner element is coupled to the optical splitter element and is operable to passively split a third transport signal including the ingress traffic to generate a drop signal including local drop traffic and a fourth transport signal including the ingress traffic. Protection switching may be provided by selectively openable switches disposed in and distributed around the rings.

Flexible open ring optical network and method

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.

Modulating a signal using a fractional phase modulator

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.

[object Object]

An optical network includes an access ring, a local ring, one or more add/drop nodes (ADNs), a first gateway and a second gateway. The access ring couples the plurality of gateways and transmits optical signals to and from the gateways, the optical signals comprising multiple wavelengths each wavelength operable to carry traffic. The local ring couples one or more of the ADNs and transmits optical signals to and from the ADNs. Additionally, the ADNs are capable of adding and dropping traffic to and from the local ring in one or more wavelengths. The first gateway is capable of receiving broadcast traffic on the access ring, the broadcast traffic transmitted in one or more wavelengths of the optical signals transmitted on the access ring and forwarding, on the access ring, a first copy of the broadcast traffic received on the access ring. The first gateway is further capable of forwarding, to the local ring, a second copy of the broadcast traffic received on the access ring The second gateway is capable of receiving local traffic originating from one or more of the ADNs on the local ring and forwarding the local traffic to the access ring. The second gateway is further capable of receiving, from the local ring, broadcast traffic forwarded to the local ring by the first gateway and terminating the broadcast traffic received from the local ring.

Optical ring network for extended broadcasting

Monitoring a bias point of an optical modulator includes receiving an optical signal modulated by the optical modulator. Photons of the optical signal are received at a photon reactive material operable to produce a reaction in response to the arrival of a predetermined number of photons. Reactions are produced in response to the arrival of the photons of the optical signal. Feedback is generated in response to the reactions. The feedback reflects the waveform of the optical signal, and indicates one or more bias points of the optical modulator.

Monitoring modulator bias using photon absorption

A demodulator comprises an input splitter, optical device sets, and couplers. The input splitter splits an input signal comprising symbols to yield a number of signals. A first optical device set directs a signal of along a first path. A second optical device set directs another signal along a second path to yield a delayed signal. At least a portion of the second path is in free space. A path length difference between the first path and the second path introduces a symbol delay between the first signal and the second signal. A coupler receives a portion of the signal and a portion of the delayed signal to generate interference, where the interference indicates a phase shift between a phase corresponding to a symbol and a successive phase corresponding to a successive symbol.

Free space demodulator for demodulating a signal

An optical network includes an optical ring that is capable of transmitting, between two or more nodes, a plurality of working traffic streams that include traffic transmitted in one of a plurality of wavelengths. A node is capable of transmitting, in a first wavelength, a first protection traffic stream associated with a first working traffic stream, in response to an interruption of the first working traffic stream. A node is also capable of transmitting, in a second wavelength, a second protection traffic stream associated with a second working traffic stream, in response to an interruption of the second working traffic stream. The optical network also includes a regeneration element capable of selectively regenerating the first protection traffic stream. The regeneration element is also capable of tuning the regeneration element to receive traffic in the second wavelength and of selectively regenerating the second protection traffic stream.

Method and system for shared optical regeneration

Monitoring a demodulator includes repeating the following for each demodulating module of one or more demodulating modules of a demodulator: receiving a first signal and a second signal from a demodulating module; introducing a relative delay between the first signal and the second signal; and asynchronously sampling the first signal and the second signal to yield samples. Image data representing the samples associated with the demodulating modules is generated. The image data indicates one or more mismatches of the demodulator.

Monitoring differential phase-shifted keying demodulation

A demodulator includes one or more modules operable to receive an input signal comprising symbols. A module receives a main signal comprising at least a portion of the input signal and splits the main signal to yield a branching signal and a remaining main signal. The branching signal travels along a first path, and the remaining main signal travels along a second path. The second path introduces a delay with respect to the first path. If there is a next module, the module sends a first portion of the remaining main signal to a next module as a main signal for the next module. The module combines the branching signal and at least a second portion of the remaining main signal to generate interference. The interference indicates a phase shift between a phase corresponding to a symbol and a successive phase corresponding to a successive symbol.

Demodulating a signal by performing consecutive beam splitting

A method for token-controlled data transmission includes receiving a token including transmission data specifying one of a plurality of data channels and a time window. A burst blocker is configured, based at least in part on the transmission data, for the selective communication of the specified data channel on an optical transmission medium having the plurality of data channels. The selective configuration of the burst blocker includes splitting the specified data channel from the plurality of data channels, configuring the burst blocker in a first configuration during a time other than the time window to rejoin the specified data channel with the plurality of data channels for transmission of the plurality of data channels toward a destination node, and configuring the burst blocker in a second configuration during the time window to block the specified data channel to prevent the transmission of the specified data channel.

Dynamic blocking of token-controlled data transmissions in communication networks

A method and system for a data centric architecture in an optical network are provided. In one embodiment, a method and system for a data centric architecture in an optical network includes an optical ring. A number of local nodes are coupled to the optical ring and are configured to receive traffic at a receiving wavelength by optically broadcasting with electrical tag discrimination. Each local node is also configured to transmit traffic at an assigned wavelength different from the transmitting wavelengths assigned to the other local nodes. The transmitting wavelengths are each transmitted at a bandwidth less than the receiving wavelength. A data center node is coupled to the optical ring and operable to receive traffic from the local nodes, sort at least some of the traffic based on the destination of the traffic, and transmit the traffic at the receiving wavelength to the destination.

Method and system for a data centric architecture in an optical network

Monitoring modulation alignment variation of optical modulators includes receiving an optical signal at an input fiber. The optical signal has been modulated by optical modulators. Photons of the optical signal are received at a photon reactive material operable to produce a reaction in response to the arrival of a predetermined number of photons. Reactions are produced in response to the arrival of the photons of the optical signal. Feedback is generated in response to reactions. The feedback reflects the waveform of the optical signal, and indicates modulation alignment variation among the optical modulators.

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Cechan Tian