Abstract: In an optical access network system in which a relay station receives a wavelength multiplexed and time-division multiplexed optical signal (WDM optical signal) from an optical network, and the relay station transmits optical signals having specified wavelengths to subscriber units, the relay station demultiplexes the WDM optical signal into a plurality of groups with one group having a plurality of optical signals having a fixed wavelength interval between signals, then divides the optical signals of each group into k branches (k is the number of subscriber units) and inputs the signals to optical switches, and by turning ON/OFF the optical switches such that they are spaced in time, inputs the branched optical signals to the respective specified subscribers units.

Abstract: An optical network system capable of directly routing optical signals without entailing multiple reception of identical wavelengths. A set wavelength output unit outputs a set wavelength. An Nk-axis filter receives an Nk-axis signal propagated through a ring of an Nk-axis direction and an Nk?1-axis signal split inside the local node, and performs filtering by removing a wavelength identical with that of the Nk?1-axis signal from the Nk-axis signal and adding the wavelength of the Nk?1-axis signal to the Nk-axis signal. An Nk-axis splitter splits the Nk-axis signal into two, one being output to outside through the ring of the Nk-axis direction while the other being output, if k<n, to a confluence with an Nk+1-axis signal, and, if k=n, to a wavelength separation filter. The filter separates a desired wavelength from the Nk-axis signal. Optical transmission media connect nodes so as to constitute an n-dimensional torus network.

Abstract: A method of transporting traffic on an optical ring includes, at one or more nodes coupled to the optical ring, splitting an incoming signal (including traffic in a plurality of sub-bands) into a first signal and a second signal. The first signal includes the traffic in a first sub-band of traffic channels and the second signal includes the traffic in the remaining sub-bands of traffic channels of the incoming signal. The method also includes receiving the traffic in the first sub-band at a bypass element, rejecting the traffic in a first portion of the first sub-band at the bypass element, and forwarding the traffic in a second portion of the first sub-band at the bypass element. In addition the method includes, combining the traffic in the second signal with the traffic in the second portion of the first sub-band for transport on the network.

Abstract: An optical switching device the size and costs of which are reduced by decreasing the number of switching elements and which can flexibly accommodate the expansion of the number of ports. An optical demultiplexing section has 2n (n=1, 2, 3, . . . ) input ports and 2m (m>n) output ports and includes demultiplexing couplers for demultiplexing input optical packets. A switch fabric section includes optical gate elements for switching optical packets outputted from the optical demultiplexing section by switch drive control. An optical multiplexing section has 2m input ports and 2n output ports and includes multiplexing couplers for multiplexing the optical packets which pass through the optical gate elements. A scheduler exercises control over an entire optical packet switching process.

Abstract: An optical switching system having a transmission node. The transmission node includes a bit pattern processing unit for processing a bit pattern of transmitted data to stabilize optical power of a frame signal light to be monitored and a frame signal light producing unit for producing frame signal light to be transmitted on the basis of the bit pattern processed by the bit pattern processing unit.

Abstract: An optical network system capable of directly routing optical signals without entailing multiple reception of identical wavelengths. A set wavelength output unit outputs a set wavelength. An Nk-axis filter receives an Nk-axis signal propagated through a ring of an Nk-axis direction and an Nk?1-axis signal split inside the local node, and performs filtering by removing a wavelength identical with that of the Nk?1-axis signal from the Nk-axis signal and adding the wavelength of the Nk?1-axis signal to the Nk-axis signal. An Nk-axis splitter splits the Nk-axis signal into two, one being output to outside through the ring of the Nk-axis direction while the other being output, if k<n, to a confluence with an Nk+1-axis signal, and, if k=n, to a wavelength separation filter. The filter separates a desired wavelength from the Nk-axis signal. Optical transmission media connect nodes so as to constitute an n-dimensional torus network.

Abstract: The present invention relates to a light source apparatus. The light source apparatus includes a plurality of optical pulse train generation sections; an optical switch section capable of selectively outputting an optical pulse train to be taken as an optical pulse train for current use; an output light generation section capable of generating continuous light of multiple wavelengths from said optical pulse train output from said optical switch section; and an optical switch control section for controlling said optical switch section to switch an output of said optical pulse train for current use from said optical switch section, in accordance with the states of respective optical pulse trains generated by said plurality of optical pulse train generation sections and without involvement of instantaneous power interruption.

Abstract: In an optical transmission system, a transmitting transceiving node generates a multiplexed optical-packet signal by performing optical wavelength multiplexing on a plurality of optical packets, and transmits the multiplexed optical-packet signal to a receiving transceiving node. The receiving transceiving node transmits the multiplexed optical-packet signal back to the transmitting transceiving node. The transmitting transceiving node detects a skew amount of the optical packet allocated to each wavelength band of the multiplexed optical-packet signal received from the receiving transceiving node, and adjusts a delay amount of the optical packet based on the detected skew amount.

Abstract: An optical switching system having a transmission node. The transmission node includes a bit pattern processing unit for processing a bit pattern of transmitted data to stabilize optical power of a frame signal light to be monitored and a frame signal light producing unit for producing frame signal light to be transmitted on the basis of the bit pattern processed by the bit pattern processing unit.

Abstract: An optical transmission system capable of time difference correction without increasing guard times, thereby improving optical packet transmission efficiency. An optical switching processor sets identical switching timing for all input ports thereof such that optical signals input from the input ports are switched at the same timing. During initialization, a time difference corrector transmits an optical dummy packet to an optical switch node, and detects synchroneity of the optical dummy packet returned thereto after being switched by the optical switch node. If synchronization error is detected, the time difference corrector adjusts the output timing of the optical dummy packet so that the timing of arrival of the optical dummy packet at the optical switching processor may coincide with the switching timing of the optical switching processor, to thereby correct the time difference between the switching timing and the arrival timing.

Abstract: In an optical switch apparatus which continuously carries out the route switching on frame signal light inputted from various routes while eliminating differences in output power value, a first delaying unit, which is interposed between a first branching unit and an input terminal, delays the input of the frame signal light to a switch module until the drive voltage supply control on the frame signal light in a drive voltage supply control unit reaches a stable condition.

Abstract: A method for communicating optical traffic in a network comprising a plurality of network nodes includes receiving traffic to be added to the network at a network node. The network is operable to communicate received traffic in an optical signal comprising one or more channels. The method also includes determining a data rate and one or more destination nodes of the received traffic and assigning the received traffic to one or more of the channels of the optical signal based on the determined data rate and the destination nodes. The method further includes configuring one or more of the network nodes to process the traffic contained in the assigned channels based on the data rate and the destination nodes of the optical traffic and communicating the traffic through network in the assigned channels of the optical signal based on the determined data rate and the one or more destination nodes.

Abstract: A method of wavelength selection control is disclosed.

Abstract: An optical packet switching system in which transmission quality, reliability, and system management in optical packet switching control are improved. An optical packet switch section includes semiconductor optical amplifiers as gate switches multistage-connected on paths along which optical packets sent from a plurality of input line cards are transmitted and performs optical packet switching by broadcasting the optical packets to a plurality of gate switches, by selecting the optical packets by ON/OFF gating operation of the gate switches, and by absorbing noise signals which flow along non-selected paths by putting gate switches at a final stage into the OFF state. A switch control section exercises ON/OFF drive control over the gate switches in the optical packet switch section on the basis of port connection requests from the plurality of input line cards so as to generate requested paths.

Abstract: A method for management of directly connected optical components includes receiving a source optical signal for communication to an optical network. The source optical signal comprises one or more source channels. The method includes monitoring optical traffic communicated on the optical network to determine one or more network channels of the optical traffic and determining network channel information of the one or more network channels. The method also includes communicating to the optical network channels of the one or more source channels that do not interfere with any of the one or more network channels.

Abstract: Each of a plurality of semiconductor optical amplifiers operates as an optical gate switch and selects an optical signal indicated by a gate control signal from an optical gate switch control unit. A plurality of photodetectors monitor the power of an optical signal input through a corresponding input port. A VOA control unit calculates an amount of attenuation corresponding to each input port based on the power of each optical signal. A variable optical attenuator attenuates the selected optical signal according to the calculated amount of attenuation in synchronization with the gate control signal.

Abstract: An optical cross-connect includes multiple input ports that each receives an optical input signal and multiple output ports that each output an optical output signal. The optical cross-connect also includes a distributing amplifier associated with each input port that generates multiple copies of the input signal received at the associated input port and multiple filter units that receive one or more of the copies and forward traffic in selected channels of particular copies. In addition, the optical cross-connect includes a combining amplifier associated with each output port that receives the traffic forwarded by one or more of the filter units and combines the received traffic into an output signal. Moreover, the optical cross-connect includes at least one upgrade input port and at least one upgrade output port expanding the capacity of the optical cross-connect, as well as associated upgrade distributing and combining amplifiers and upgrade filter units.

Abstract: In the optical module, the number of optical components is decreased, so that the costs of the device are reduced, and so that optical loss is reduced. The present device comprises: an optical gate array in which a plurality of optical gate switches each employing a semiconductor optical amplifier element are arranged in parallel; a dividing/combining unit including: a plurality of first ports connected one to each of the plurality of optical gate switches forming the optical gate array; and a second port which performs dividing/combining of light with the first port; and an optical amplifier connected to the second port of the dividing/combining unit, wherein the optical gate array, the dividing/combing unit, and the optical amplifier are formed in an integrated manner.

Abstract: An optical transmission system capable of time difference correction without lengthening guard times, thereby improving optical packet transmission efficiency. A switching processor sets identical switching timing for all input ports thereof such that signals input from the input ports are switched at the same timing. When an optical dummy packet is received, the switching processor switches the optical dummy packet to be returned to the originating node. A time difference corrector detects synchroneity of the switched and looped-back optical dummy packet and, if asynchronism is detected, varies readout timing until synchroneity is attained, thereby correcting the time difference so that the optical dummy packet may fit in the switching time range and thus can be switched normally.

Abstract: Optical add/drop nodes are used in a network having a pair of optical transmission paths for transmitting optical signals in opposite directions to each other. Each add/drop node comprises a variable split ratio optical coupler for splitting an optical signal output from a transmitter. The split ratio of the variable split ratio optical coupler is set such that the optical power levels of the signals added through the respective optical add/drop nodes are equal to one another respectively on the pair of optical transmission paths.