Abstract: A wavelength selective switch includes a wavelength dispersing element, a wavelength converging element, multiple transmission control elements, and a controller. The wavelength dispersing element performs wavelength dispersion of input signal light. The transmission control element divides input signal light into wavelength bands within a channel band and transmits or cuts off the divided input signal light. The wavelength converging element converges signal light having respective wavelengths produced from the transmission control elements for output. The controller controls a transmittance of the transmission control element of at least one of the low and high frequency sides in a channel band.

Abstract: The present invention provides a directionless optical architecture for reconfigurable optical add/drop multiplexers (ROADMs) and wavelength selective switches (WSSs). The directionless architecture utilizes a directionless wavelength switch coupled between client devices and ROADMs/WSSs to eliminate the need to hard-wire client devices to a wavelength division multiplexed (WDM) network. Accordingly, client device connections can be automatically routed without manual intervention to provide a highly resilient network design which can recover route diversity during failure scenarios. Additionally, the present invention minimizes deployments of costly optical transceivers while providing superior resiliency. Further, the present invention couples the directionless optical architecture and associated optical protection mechanisms with existing mesh restoration schemes to provide additional resiliency.

Abstract: An optical signal demodulator includes: an obtaining unit configured to obtain a spectrum of an optical signal generated by a second signal being superimposed on a first signal using frequency modulation; an identifying unit configured to identify a peak wavelength which is a wavelength corresponding to a peak position of the spectrum; and a demodulating unit configured to demodulate the second signal from the optical signal using a wavelength-variable filter to which a transmitted wavelength band has been set based on the peak wavelength.

Abstract: A packet-optical integrated transport apparatus includes a packet transmitter for outputting single-wavelength signal multiplexed to a preset channel on the basis of packet traffic or circuit traffic input from a metro access region, and an optical transmitter for multiplexing the single-wavelength signal output from the packet transmitter to a multi-channel wavelength signal and adding or dropping the multiplexed multi-channel wavelength signal to or from a node. The apparatus further includes a system controller for transmitting constituent element initialization information to the packet transmitter and the optical transmitter and receiving constituent element operation status information.

Abstract: An optical signal transmission method includes: obtaining a signal identifier of data to be sent; obtaining corresponding optical frequency slot distribution information according to the signal identifier; and determining a corresponding carrier according to the obtained optical frequency slot distribution information, using the determined carrier to carry the data to be sent to generate an optical signal, and sending the generated optical signal. The optical signal transmission method provided in the present invention does not fix the optical frequency slot distribution into a wavelength identifier, the number of optical frequency slots is not limited by the wavelength identifier field length, and the data to be sent can be transmitted in an optical network by being carried on the carrier determined according to multiple optical frequency slots.

Abstract: A colorless, directionless ROADM includes a pair of contentioned add and drop wavelength-selective optical switches, an input wavelength-selective optical switch having one input port, and an output wavelength-selective optical switch having one output port. Unintended input-to-output port couplings, which appear in the “contentioned” add and drop switches, can be mitigated by the input and output wavelength-selective optical switches carrying the through traffic.

Abstract: Switching architectures for WDM mesh and ring network nodes are presented. In mesh networks, the switching architectures have multiple levels—a network level having wavelength routers for add, drop and pass-through functions, an intermediate level having device units which handle add and drop signals, and a local level having port units for receiving signals dropped from the network and transmitting signals to be added to the network. The intermediate level device units are selected and arranged for performance and cost considerations. The multilevel architecture also permits the design of reconfigurable optical add/drop multiplexers for ring network nodes, the easy expansion of ring networks into mesh networks, and the accommodation of protection mechanisms in ring networks.

Abstract: Provided is an optical network system and optical network unit (ONU) structure enabling a passive optical access network having a meshed structure with at least two central nodes and plurality of ONUs. One embodiment employs a partially or fully meshed structure of optical fibers between customer locations and multiple optical line terminal (OLT) locations creating a passive optical access network. The ONUs can communicate with a neighboring OLT or ONU using a symmetrical or asymmetrical TDM scheme, and convert between the different TDM schemes. For this purpose, the ONU structure includes two transceiver units, one connected to the western network port and the other to the eastern. The ONU can establish communication between either network port and a further ONU or an OLT, with the ONU controller adapted for passing through data, and converting TDM schemes.

Abstract: The invention relates to a method of operating an optical transmission system (100), wherein an optical signal (s, s1) is transmitted (200) through at least one component (102) of said optical transmission system (100) which exhibits spectral phase ripple, and wherein a phase of at least one frequency component of said optical signal (s, s1) is altered (210) by phase influencing means (110) to at least partly compensate for said phase ripple of said at least one component (102), whereby a phase ripple compensated signal (s2) is obtained.

Abstract: A system and method for selecting ghost channels in an optical communication system, including components configured to examine an optical communication channel within a node of the optical communication system, examine a neighbor channel of the optical communication channel, determine whether using the neighbor channel as a ghost channel will create an undesirable level of risk of feedback within the optical communication system, if using the neighbor channel as a ghost channel will not create an undesirable level of risk of feedback, determine whether the neighbor channel is currently used as a ghost channel, and if the neighbor channel is not currently used as a ghost channel, select the neighbor channel as a ghost channel.

Abstract: A method implemented in a network apparatus used in a wavelength division multiplexing (WDM) optical network is disclosed. The method includes (a) finding K-shortest routes between each node pair (s, d), where s, d?V and |V|?K, where V is a set of reconfigurable optical add-drop multiplexer (ROADM) nodes, (b) selecting unconsidered node pair (s, d), (c) selecting unconsidered route k between nodes s and d out of the K-shortest routes, (d) finding a bit map of route k by performing bit-wise logical AND operation on bit vectors of fibers along route k, (e) selecting unconsidered line rate l out of offered set L of line rates, and (f) finding a probability ?ls,d,k of provisioning a connection with line rate l. Other apparatuses, systems, and methods also are disclosed.

Abstract: The optical channel monitor includes a polarization adjuster, a wavelength divider, a polarization divider, a first intensity detector, and a second intensity detector. The polarization adjuster adjusts the plane of polarization of a first optical signal to a first direction and the plane of polarization of a second optical signal to a second direction. The wavelength divider divides each of the optical signals multiplexed on the first and second optical signals, in accordance with the wavelengths. The polarization divider divides each of the divided optical signals, based on the direction of the plane of polarization. The first intensity detector receives an optical signal whose direction of the plane of polarization is the first direction among the divided optical signals. The second intensity detector receives an optical signal whose direction of the plane of polarization is the second direction.

Abstract: A monitoring apparatus, that monitors a wavelength tunable optical filter for filtering an optical signal to which a frequency modulation component is added, includes: an optical filter configured to filter the optical signal output from the wavelength tunable optical filter; a detector configured to detect amplitude of the frequency modulation component included in the optical signal output from the optical filter; a generator configured to generate an output-side amplitude distribution representing a distribution of the amplitude of the frequency modulation component detected by the detector, by sweeping a transmission wavelength of the optical filter; and a monitoring unit configured to monitor arrangement of a transmission wavelength band of the wavelength tunable optical filter with respect to a spectrum of the optical signal based on the output-side amplitude distribution generated by the generator.

Abstract: A method for optical layer traffic grooming includes receiving at least two optical input signals into respective optical receivers, each optical receiver having a photodetector for converting the respective optical input signal into a respective electrical signal; a grooming processor responsive to the electrical signals, the grooming processor being a radio frequency RF processor for processing the electrical signals at a subcarrier level to produce an RF orthogonal frequency division multiplexing signal OFDM signal; and modulating the groomed RF OFDM signal at a transmitter for conversion of the groomed RF OFDM into an optical signal.

Abstract: A communications network transport node comprising an optical add-drop multiplexer (OADM), comprising optical signal processing apparatus, electrical signal routing apparatus, and a packet switch. Each optical signal processing apparatus comprises an optical input, an optical output, optical-to-electrical (O-E) signal conversion apparatus arranged to receive input optical channel signals and to convert each into an input radio frequency (RF) modulated electrical channel signal, and electrical to optical (E-O) signal conversion apparatus arranged to receive output RF modulated electrical channel signals and to convert each into an output optical channel signal. The electrical signal routing apparatus determines which input RF modulated electrical channel signals are to be dropped, and routes these to the electrical drop outputs, and which are to be transmitted, and routes these to a selected E-O apparatus.

Abstract: An optical repeater formed in an optical passive component passively relays an incoming multiplexed optical signal. The repeater has an optical decoder decoding the multiplexed optical signal, and an optical encoder encoding an optical signal from a termination unit connected to the repeater. The repeater further includes a first optical path switch outputting an incoming multiplexed optical signal to the optical decoder and outputting the optical signal delivered from the optical decoder, a second optical path switch outputting the optical signal coming from the first optical path switch to the termination unit, and a third optical path switch outputting the optical signal coming from the second optical path switch to the encoder and outputting the optical signal delivered from the encoder.

Abstract: The invention relates to a method for operating a controllable selective optical add/drop channel for a fiber-optic communication system provided with 2N of wavelength-division multiplexing channels, whose optical frequencies are returnable at a constant frequency separations ?v between adjacent channels, with the aid of the inventive controllable optical add/drop multiplexers (70, 80, 90) that comprise multi-stage structures of optical filters ({75-i}, {85-i}, {95-i}), that are connected in a different manner and provided with devices, for example electro-optical and thermo-optical phase shift devices, for controllable tuning the transmissions characteristics thereof. The optical filters are embodied in the form of single-stage (20), two-stage (40) and/or multi-stage (60) asymmetric Mach-Zehnder interferometers. The controllable optical add/drop multiplexer can be produced according to integrated optic technique in the form of monolithic solid-state device.

Abstract: Optical network apparatus comprises an optical add drop multiplexer (10) comprising an optical signal input (11) and an optical signal output (12). An add input path (15) is connected to the optical signal output (12) for receiving a wavelength channel to be added. A drop output path (16) is connected to the optical signal input (11) for outputting a wavelength channel to be dropped. A through signal path (18) is connected between the optical signal input (11) and the optical signal output (12). An optical filter (20) is positioned in the add input path (15) for filtering an optical signal received on the add input path (15) from an optical terminal (40). A reflective device (30) in the add input path (15) is arranged to form an optical seed signal by returning at least a portion of the filtered optical signal. The optical seed signal is for use in seeding an optical transmitter at the optical terminal (40).

Abstract: A network element (10) comprises: a first optical input section (1), a first optical output section (2), a second optical input section (3) and a second optical output section (4) a first and second insertion and extraction modules (30, 40), each of said insertion and extraction modules comprising a wavelength selection switch (31, 41), a first optical coupler (8) comprising two bidirectional branches (21, 22) respectively connected to the first selectable port of the first and second insertion and extraction modules, and a second optical coupler (11) comprising two bidirectional branches (23, 24) respectively connected to the second selectable port of the first and second insertion and extraction modules.

Abstract: The present disclosure provides reconfigurable optical add drop multiplexer (ROADM) node automatic topology discovery systems and methods providing a mapping of optical connections within a mesh optical network that includes tunable lasers and multi-degree ROADM's with colorless/directionless add/drop. The present disclosure may include additional transceiver, receiver, and add/drop filter equipment integrated in or disposed at a ROADM degree. This equipment supports a so-called topology wavelength which is one of a plurality of wavelengths supported by a wavelength division multiplexed (WDM) system that is dedicated and used solely for topology discovery. The topology wavelength may be utilized by the system to detect interconnects between ROADM degrees and between XCVRs/CDMDs. Further, the automated topology discovery may be integrated within a management system and/or control plane.

Abstract: Systems and methods are described that that dynamically configure high-speed data link lightpaths between access routers and backbone routers at geographically dispersed locations to reassign traffic when a backbone router fails or is removed from service. Embodiments reduce the quantity of backbone router ports used in dual backbone router-homed networks.

Abstract: The present invention relates to a method, an apparatus, and a system for processing a flexible-rate signal. A signal from a client side is encapsulated to n optical channel data unit ODU signals. The n ODU signals are encapsulated to a flexible optical channel transport unit OTU signal. A nominal bit rate of the flexible OTU signal varies according to a value of n and the n is an integer greater than or equal to 1.

Abstract: A system to provide carrier frequency control in an optical network includes a first network element monitoring performance information and a second network element coupled to the first network element by the optical network. The second network element receives performance information from the first network element using an administration channel bandwidth, and modifies a carrier frequency associated with the second network element based on the performance information such that the carrier frequency is aligned to a center of a signal channel bandwidth. A method of providing carrier frequency control includes transmitting performance information by the first network element to the second network element using an administration channel bandwidth, and modifying the carrier frequency by the second network element based on the performance information such that the carrier frequency is aligned to the center of the signal channel bandwidth.

Abstract: Provided is an optical apparatus including: wavelength separation units corresponding to the respective routes, each of which divides a wavelength multiplexed optical signal of one route into M wavelength groups (M is an integer satisfying N×M=the number of multiplexed wavelengths of the wavelength multiplexed optical signal of one route), each of which includes N wavelengths (N is an integer of 2 or more); and M wavelength separation blocks, each of which is input with a plurality of the wavelength groups divided by the different wavelength separation units and outputs optical signals with any one or a plurality of wavelengths included in the input wavelength groups to N coherent transponders. Accordingly, it is possible to flexibly adapt to extension in wavelength or extension in route in units of a wavelength separation block and/or wavelength multiplexing block.

Abstract: Optical networks are increasingly employing optical network nodes having multiple interfaces to allow a node to direct optical signals received at any interface to any other interface connected to the node. Constructing a larger wavelength selective switching (WSS) module used in such a node can be complex and expensive. A method an apparatus for constructing a large WSS using parallelism is provided. In example embodiments, a larger WSS may include multiple parallel non-cascaded smaller WSSs and an optical coupler configured to optically couple the multiple parallel, non-cascaded smaller WSSs. This technique may be used to construct both N×1 and 1×N WSSs. Because the technique employs multiple parallel, non-cascaded WSSs, all inputs of a larger N×1 WSS and all outputs of a larger 1×N WSS are available receive or transmit external signals rather than being rather than being unavailable due to, for example, cascading smaller WSS devices together.

Abstract: An optical packet switching device (20) comprises an input section (9) able to receive an optical signal comprising data packets (60) carried by wavelength channels, a transit section (30) comprising optical paths (31) to ensure the transparent transit of the respective wavelength channels, several selector elements (34) which can be switched in packet mode to selectively block or allow an individual data packet to pass through, and a control unit able to receive signalling information about the data packets received in the input section and to control a selector element corresponding to the wavelength channel to block or allow said data packets to pass, said control unit maintaining the selector element (34) in a blocking state during the time windows in which no data packets are received on said wavelength channel.

Abstract: A system and method for sizing transponder pools in a dynamic wavelength division multiplexing optical network having selected nodes designated to have a shared transponder pool is presented.

Abstract: An optical switching device includes a optical add/drop multiplexer that at least adds an optical signal into and/or drops an optical signal from wavelength division multiplexed light that is wavelength division multiplexed optical signals; a plurality of amplifiers that are disposed on optical paths included in the optical add/drop multiplexer and that can use supplied pump light to amplify the optical signals; an optical source that generates the pump light; and an optical switch that supplies the generated pump light to any one of the amplifiers.

Abstract: An apparatus comprising one or more optical amplifiers coupled to an optical link and configured to amplify a plurality of Wavelength Division Multiplexing (WDM) channels that are transmitted at a plurality of wavelengths on the optical link, and a processor coupled to the optical link and configured to add, delete, or both a plurality of WDM channels in the optical link based on an allowed power ratio indication for the WDM channels, wherein the allowed power ratio indication is calculated based on a plurality of gain change representations for the WDM channels at a plurality of power ratios and on a link budget requirement for the optical link.

Abstract: An optical packet switching apparatus includes (i) an optical packet switch for switching the route of an inputted optical packet signal and outputting the inputted optical packet signal, (ii) an input-side packet density monitoring unit for detecting the packet density of optical packet signals inputted to the optical packet switch, (iii) a first input-side optical amplifier provided on an input side of the optical packet switch, (iv) a first input-side variable optical attenuator (VOA) provided posterior to the optical amplifier, (v) a storage for storing the gain characteristics in relation to the packet density at the first input-side optical amplifier, and (vi) an input-side VOA control unit for controlling the attenuation by the first input-side VOA in such a manner as to compensate for the gain fluctuations due to the variations in the packet density at the first input-side optical amplifier, based on the packet density and the gain characteristics.

Abstract: An optical transmission system includes a plurality of optical nodes that transmits wavelength multiplexing light including a plurality of signal light components having different wavelengths, wherein each of the optical nodes includes superimposed signal light generation circuit which superimposes a low frequency signal having a common frequency on a corresponding signal light component included in the wavelength multiplexing light; low frequency signal extraction circuit which extracts a low frequency signal having a frequency of a given range from a corresponding signal light component; and pass-through node number measurement circuit which measures, for each of the signal light components, a pass-through node number based on the frequency of the low frequency signal extracted by the low frequency signal extraction circuit, the pass-through node number being the number of optical nodes through which the signal light component has passed before being transmitted to a specific optical node.

Abstract: In an embodiment of the invention, an optical transport apparatus comprises first wavelength-division-multiplex optical signal processing units each corresponding to each of transmission lines, an interface unit connected to a client apparatus and converting a client signal to and from a signal to be wavelength-division multiplexed, and a second wavelength-division-multiplex optical signal processing unit connected to the interface unit and receiving the signal to be wavelength-division multiplexed from the interface unit. Each of the first wavelength-division-multiplex optical signal processing units includes a wavelength selective switch including inputs, multiplexing signals selected from optical input signals received from the inputs and outputting the multiplex signal to a corresponding transmission line.

Abstract: The present disclosure describes a reconfigurable optical add-drop multiplexer. The reconfigurable optical add-drop multiplexer includes a first optical equalizer to precompensate a received optical signal for optical filtering effects to produce a first compensated optical signal. A first interleaver, coupled to the first optical equalizer, separates the first compensated optical signal into an odd optical signal and an even optical signal. A plurality of wavelength selective switches processes the odd optical signal and the even optical signal. A second interleaver, combines the odd optical signal and the even optical signal to produce a combined optical signal. A second optical equalizer, coupled to the second interleaver, postcompensates the combined optical signal for optical filtering effects to produce an output optical signal.

Abstract: A wavelength path communication node apparatus includes a wavelength path demultiplexer (321) which demultiplexes branched optical signals input to wavelength multiplexing ports into wavelength path signals, and outputs the wavelength path signals from wavelength demultiplexing ports corresponding to the respective wavelengths, a wavelength path multiplexer (322) which outputs wavelength path signals input to wavelength demultiplexing ports from wavelength multiplexing ports corresponding to the wavelengths of the wavelength path signals, a plurality of transponders (331) each of which converts a wavelength path signal input to a wavelength path transmission port into a client transmission signal to transmit the client transmission signal, and converts a received client reception signal into a wavelength path signal of a wavelength to output the wavelength path signal from a wavelength path reception port, a demultiplexing system optical matrix switch (323) which switches and connects the wavelength demultipl

Abstract: A method of configuring an optical path, comprising: selecting a path from a first to a second node in an optical communications network; identifying each wavelength that may be used continuously across the path and selecting a transmission wavelength for the optical path one of the identified wavelengths for which: a fixed wavelength direction-bound add/drop transponder add operable at said wavelength is available at each node; if that first requirement is not met, a fixed wavelength direction-bound add/drop transponder or a fixed wavelength directionless add/drop transponder operable at said wavelength is available at each node; and if that second requirement is not met, a tunable wavelength direction-bound add/drop transponder or a tunable wavelength directionless add/drop transponder operable at said wavelength is available at each node.

Abstract: An optical network including at least one optical network node that receives an optical signal for either transmission or reception. The optical network node analyzes the optical signal and applies communication protocols necessary for optical transmission or reception of the optical signal to or from the optical network. At least one communication module is coupled to the at least one optical network node either decodes or encodes the optical signal by identifying or adding at least one wavelength to the optical signal for security.

Abstract: An optical apparatus includes a first optical amplifier for adjusting an output value to a constant level; an optical signal processor located before the first optical amplifier and processing the optical signal; a second optical amplifier located before the optical signal processor and subjected to automatic gain control for adjusting a gain constant; and a controller detecting a level of the optical signal at an output of the second optical amplifier. The controller adjusts a level of an output value of the first optical amplifier such that the level of the optical signal at the output of the second optical amplifier is held at the optimum value if the detected level of the optical signal differs from an optimum value, compensates for a loss caused in the optical signal processor and maintains the level of the optical signal at the output of the second optical amplifier at the optimum value.

Abstract: An optical transmission device that is connected to transmission paths of a network, that performs optical communication according to a wavelength division multiplex format and that transmits optical signals over the transmission paths according to path types that have been set to wavelengths of the optical signals, including an upper limit value storage section that stores an upper limit value of the number of operational wavelengths that is the number of wavelengths to which the path types are set; an acceptance section that accepts a changing request that requests that the number of operational wavelengths be changed; and a license determination section that decides the number of operational wavelengths, wherein if the number of wavelengths that has been changed according to the accepted changing request is equal to or smaller than the stored upper limit value, the license determination section newly sets the changed number of wavelengths for the number of operational wavelengths.

Abstract: An optical ring network architecture including a number (N) of multi-add/drop filters, such as filters formed using pairs of frequency routers. Each multi-add/drop filter is coupled to two other multi-add/drop filters using N-2 transmission media, such as optical fibers, to form a ring. The network includes a number (N) of terminal stations associated with the multi-add/drop filters. A terminal station (p) is coupled with, and receives information from, its associated multi-add/drop filter (p) through a single optical fiber. The terminal station p is coupled with, and transmits information in a first direction around the ring to, a multi-add/drop filter p+1 through a single optical fiber. Communications from terminal station p to each other terminal station in the first direction are assigned one of N-1 wavelengths where no two wavelengths on a given optical fiber are associated with communications between terminal stations in the same direction.

Abstract: A reconfigurable optical add/drop multiplexer (ROADM) with a multiplexer, demultiplexer, and a wavelength cross-connect unit provides directionless capabilities. The ROADM allows a signal not to be limited to a particular direction when added at an optical network node, for example. The signal can be sent to other directions of the optical network node. Furthermore, the ROADM allows the wavelengths of add and drop signals to be changed and hence is “colorless.

Abstract: There is provided an optical network system in which optical signals modulated by each of at least two modulation methods are wavelength-division-multiplexed and transferred, including: an optical transmitter configured to transmit first optical signals modulated by each of at least two modulation methods; an add-drop multiplexer configured to drop second optical signals from wavelength-division-multiplexed optical signals transferred in the optical network system, and add the first optical signals to the wavelength-division-multiplexed optical signals; an optical receiver configured to demodulate the second optical signals corresponding to each of at least two modulation methods; and a controller configured to control wavelengths of the first optical signals, the second optical signals and the wavelength-division-multiplexed optical signals so as to rearrange wavelengths of the first optical signals, the second optical signals and the wavelength-division-multiplexed optical signals so that optical signals mo

Abstract: A telecommunications module includes an optical wavelength division multiplexer/demultiplexer configured to demultiplex a first optical signal input into the telecommunications module into a plurality of different wavelengths, a fiber optic splitter configured to split a second optical signal input into the telecommunication module into a plurality of optical signals, and a plurality of optical add/drop filters, each of the optical add/drop filters configured to combine one of the optical signals that has been split by the fiber optic splitter and one of the wavelengths that has been demultiplexed by the optical wavelength division multiplexer/demultiplexer into a combination output signal that is output from the telecommunications module.

Abstract: A method for managing an optical network having a plurality of nodes interconnected by a plurality of fiber links includes installing one or more active reconfigurable optical add/drop multiplexer (ROADM) cards into a node and installing a spare ROADM card into the node. The one or more active ROADM cards are configured to pass optical traffic to and from the optical network. The installed spare ROADM card is remotely activated to pass optical traffic to and from the optical network, subsequent to configuring the one or more active ROADM cards, based on one of: an event or expiration of a time period.

Abstract: Optical nodes in an optical network may provide directionless, colorless, contentionless, and gridless transmission, reception, and switching of optical signals in which a non-fixed number of optical channels and a non-fixed bandwidth for each optical channel is used. Optical nodes can use the full extent of the optical bandwidth due to the absence of channel spacing.

Abstract: A device includes a first band coupler, a first reconfigurable optical add-drop multiplexer (ROADM), a second ROADM, and a second band coupler. The first band coupler is configured to decouple a regular band and an extended band. The first ROADM is configured to add or drop one or more frequencies in the decoupled regular band to produce a first output in the regular band. The second ROADM is configured to add or drop one or more frequencies in the decoupled extended band to produce a second output in the extended band. The second band coupler is configured to couple the first output and the second output to produce a third output occupying the regular band and the extended band.

Abstract: A plurality of output units 31, each having first output ports and second output ports, output received input wavelength-specific optical signals from the output ports. Switchers 32 output the wavelength-specific optical signals output from the first output ports of the output units 31 to respective different optical paths. Output units 31 correspond respectively to a plurality of routes for transmitting wavelength-multiplexed optical signals. Each of output units 31 receives a wavelength-specific optical signal included in the wavelength-multiplexed optical signal transmitted through a corresponding route and wavelength-specific optical signals output from the second output ports of other output units, as the input wavelength-specific optical signals, and output each of the wavelength-specific optical signals from either the first output ports or the second output ports depending on the wavelength of the wavelength-specific optical signal.

Abstract: An optical branching and insertion device includes an optical splitter that branches an input optical signal, and outputs the branched optical signal from a first output port and a second output port; a wavelength selective switch that allows passage of an optical signal of a predetermined wavelength from among optical signals input to a first input port from the first output port, and outputs the optical signal of the predetermined wavelength and an optical signal inputted from a second input port; and a processor that executes a process to expand a band through which the optical signal of the predetermined wavelength is allowed to pass, the process being executed when a channel allocated to a wavelength of the optical signal inputted from the second input port and a channel allocated to the predetermined wavelength are not adjacent.

Abstract: Described are an FSK modulator and a method for large-alphabet FSK modulation. The FSK modulator and the method are based on filtering of a multi-tone optical source such as a mode-locked laser which provides a comb distribution of tones. A frequency-selective component selects for transmission a subset of the tones. In various embodiments the frequency-selective component is a Mach-Zehnder interferometer filter or a microring resonator filter. A second frequency-selective component selects a subset of the tones from the comb distribution provided by the first frequency-selective component. Still more frequency-selective components can be used according to the number of tones supplied by the multi-tone optical source to the FSK modulator. The optical signal exiting the last frequency-selective component includes only a single tone which corresponds to the symbol to be transmitted.

Abstract: The present invention provides a directionless reconfigurable optical add/drop multiplexer (ROADM) system. The present invention provides a scalable all-optical switching element that includes a combination of 1×N wavelength selective switches (WSS), 1×N splitters/combiners, optical amplifiers, and tunable filters to provide a fully non-blocking solution which can be deployed in a scalable manner. The 1×N splitters are configured to split multiples copies of a plurality of drop wavelengths which can be amplified and sent to a tunable filter which selects out a particular wavelength for drop. The 1×N combiners are configured to combine multiple add wavelengths for egress transmission.

Abstract: The invention facilitates optical signals generated from customer premise equipment (CPE) at the edges of the metro domain networks. The CPEs are connected to extension terminals that transform the optical signal originating at the CPE into a suitable format for long haul transmission. The optical signal then propagates to a primary terminal where the signal is multiplexed with other optical signals from other extension terminals. The multiplexed signals are then transmitted over LH or ULH network to a second primary terminal where the signal is then demultiplexed from other optical signals and transmited to the proper extension terminal. At the extension terminal, the demultiplexed optical signal is transformed from its LH format back into a format suitable for interconnection to a CPE. Using this architecture, the signal under goes optical-to-electrical conversion only at the extension terminals or end points. These end points can be located in lessee's facility.