Abstract: One or more overlay wavelengths are applied to a GPON architecture to provide sufficient, cost-effective forward bandwidth per home for targeted, unique narrowcast services to allow traditional HFC operators to use a PON architecture with their existing HFC equipment. A separate return path capability using a separate coaxial cable with RF signals to the GPON may also be used. This return capability may be provided either by a fiber optic link or coaxial link from the home.

Abstract: The present disclosure generally pertains to an arrayed media converter (AMC) that has an array of Wavelength Division Multiplexing-Passive Optical Network (WDM-PON) Optical Network Units (ONUs) for terminating an optical channel in the feeder or distribution portion of a telecommunication network. The ONU converts an optical signal from the optical channel into at least one electrical signal for transmission to a customer premises. Thus, the AMC serves as an interface between at least one WDM-PON link and at least one conductive connection, such as a twisted pair. In one exemplary embodiment, the AMC comprises a sealed housing that is environmentally hardened to protect the AMC from environmental conditions, including changes in weather. Such an AMC may be used to provide a robust, cost effective Fiber To The Curb (FTTC) solution, but the AMC may be used at other points within the network, if desired.

Abstract: The present invention discloses a method for realizing source routing in a blocking cross network. Link state advertisement information diffused in the network carries cross constraint characteristic information, and a call initiating node checks a path tree and gets a service path according to the cross constraint characteristic information included in the link state advertisement information in the network; the cross constraint characteristic information includes physical transmission link layer constraint information of a link in a node, which is called link switching constraint information, and constraint information of each wavelength channel in the link, which is called wavelength constraint characteristic information. The present invention also discloses an apparatus for realizing source routing in a blocking cross network.

Abstract: The present disclosure provides a transmission system, apparatus and method to provide for variable channel spacing in multiplexed or combined optical signals for transmission over a network infrastructure. The channel spacing may be monitored and maintained at desired values in order to maximize the channel density under various conditions related to the network infrastructure. The individual carrier frequencies associated with each signal channel of the transmission system may be individually controlled to define the desired channel. The channel spacing may be altered to provide for higher channel densities increasing system capacity, or to provide for lower channel densities improving the overall reach of the transmission system. The channel spacing may be continuously monitored and maintained at desired values allowing for rapid and automated reconfiguration of the transmission system, which may result in maximized capacity and reduced costs.

Abstract: A system comprising a first optical line terminal (OLT) comprising a first integrated optical network unit (ONU), and a first OLT transceiver, and a second OLT coupled to the first OLT, wherein the second OLT comprises a second integrated ONU, and a second OLT transceiver. Included is a first OLT comprising an optical transceiver, at least one processor coupled to the optical transceiver, wherein the processor working in conjunction with the optical transceiver is configured to determine an upstream wavelength corresponding to a second OLT, join, via a first ONU in the first OLT, the second OLT using the upstream wavelength corresponding to the second OLT, and transmit data to the second OLT by the first OLT via the first ONU, wherein the second OLT comprises a second ONU.

Abstract: A distribution node of a passive optical network (PON) comprises a first port for receiving a first optical continuous envelope modulated downstream data signal at a first wavelength (?C) from a first optical line termination unit (OLT1) and a second port for receiving a second optical continuous envelope modulated downstream data signal at a second wavelength (?L) from a second optical line termination unit (OLT2). A first converter (FBG-1) performs continuous envelope modulation-to-intensity modulation conversion of the first optical downstream data signal and forwards the converted first optical downstream data signal (?C) to the first group of optical network units (ONU1 . . . N). A second converter (FBG-2) performs continuous envelope modulation-to-intensity modulation conversion of the second optical downstream data signal and forwards the converted second optical downstream data signal (?L) to the second group of optical network units (ONUN+1 . . . 2N).

Abstract: A system for routing signals in a Distributed Antenna System includes a plurality of local Digital Access Units (DAUs) located at a Local location. Each of the plurality of local DAUs is coupled to each other and operable to route signals between the plurality of local DAUs. Each of the plurality of local DAUs includes one or more Base Transceiver Station (BTS) RF connections. Each of the plurality of BTS RF connections is operable to be coupled to one of one or more sectors of a BTS. The system also includes a plurality of remote DAUs located at a Remote location. The plurality of remote DAUs are coupled to each other and operable to transport signals between the plurality of remote DAUs.

Abstract: Provided is a multi-wavelength optical source generator. The multi-wavelength optical source generator includes: a gain part generating a plurality of lights through a plurality of gain waveguides; a reflective part transmitting or reflecting lights provided from each of the plurality of gain waveguides according to a wavelength; and a multiplexing part multiplexing a plurality of lights transmitted and outputted through the reflective part.

Abstract: A method for processing data in an optical network element are provided, wherein the optical network element comprises a local oscillator operating at a first frequency; wherein an incoming data stream is received at a second frequency; wherein the incoming data steam is processed using the first frequency; wherein a first pattern is searched in the incoming data stream; wherein a second pattern is searched in the incoming data stream; and wherein the first pattern corresponds to the first frequency being in the spectrum on one side of the second frequency and the second pattern corresponds to the first frequency being in the spectrum on the other side of the second frequency. Also, a corresponding optical network element and a communication system comprising at least one such optical network element are suggested.

Abstract: Systems and methods for enabling different network nodes of a network access system to share a backhaul communication link are disclosed. In one embodiment, the method includes: connecting a first modem to a first node of the network access system; connecting a second modem to a second node of the network access system; connecting the first modem to a first port of a splitter filter; connecting the second modem to a second port of the splitter filter; and connecting a backhaul communication link to a third port of the splitter filter, which is configured to multiplex signals transmitted by the modems onto the backhaul communication link, wherein the frequency spectrum of the signal transmitted by the first modem does not overlap substantially with the frequency spectrum of the signal transmitted by the second modem.

Abstract: A data transmission network comprising: a base comprising: a base light source and a base light detector; a plurality of nodes, each node comprising a node light source and a node light detector; and a plurality of optical fibers arranged to form a optical fiber network. Each optical fiber is arranged to receive light from the base light source, transmit the light received from the base light source to one or more of the node light detectors via an air gap, receive light from one or more of the node light sources via an air gap, and transmit the light received from the node light source(s) towards the base light detector.

Abstract: An optical communication system and a method for data processing in an optical network are provided, the optical network including a first optical transmission group for generating a first plurality of wavelengths in a downstream direction, a second optical transmission group for generating a second plurality of wavelengths in the downstream direction and a plurality of optical network units for receiving the first and second plurality of wavelengths, wherein the plurality of optical network units are configured to change between a first mode and a second mode of data transmission, the method comprising the steps of allocating the wavelengths associated with the optical network units in the first mode of data transmission in the first optical transmission group, allocating the wavelengths associated with the optical network units in the second mode of data transmission in the second optical transmission group and deactivating the second optical transmission group.

Abstract: Provided is a wavelength division multiplexing transmission apparatus that enables operation control of transponders each carrying an FBTL optical module from the monitoring control unit by the same operation control as one for the transponders each carrying an NB optical module with four wavelengths assigned. For that purpose, the wavelength division multiplexing transmission apparatus includes the transponders for converting optical signals from wideband wavelengths to narrowband wavelengths, and a monitoring control unit for controlling the transponders by instructions from an operator.

Abstract: Methods, systems, and apparatus guarantee bandwidth for a network transaction. A network is logically organized as a tree having a plurality of nodes. Each node can guarantee service for a network transaction through the network. Each node monitors its traffic and reserves predefined amounts of unused bandwidth with its adjacent node. If a particular node needs additional bandwidth, that node borrows the bandwidth from its adjacent node.

Abstract: A laser system includes an array of lasers that emit light at a number of different, fixed wavelengths. A group of optical transport systems connect to the laser system. Each of the optical transport systems is configured to modulate data signals onto the light from the laser system to create optical signals and transmit the optical signals on one or more optical fibers.

Abstract: Various architectures for implementing multi-band reconfigurable optical add-drop multiplexing with converged signal addition and removal are provided. Under the described architectures, channel isolation is improved, performance requirements for switching elements are lower, and it may be possible to reduce the number of line side switching elements by a factor of two. The use of additional spectrum per fiber with the described architectures results in fewer required ports per switching element. The degree of contention at signal addition and removal is also reduced. Moreover, the architectures support optical networks with higher capacities per fiber and therefore conserve fiber assets. The architectures are modular in nature, allowing a network to be deployed in a single-band setting and later upgraded to support multiple bands. This Abstract is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

Abstract: A wavelength division multiplexing (WDM)-time division multiplexing (TDM) passive optical network (PON) remote terminal (RT) is provided. The wavelength division multiplexing (WDM)-time division multiplexing (TDM) passive optical network (PON) remote terminal (RT), includes: a WDM-TDM converter configured to convert a WDM downstream optical signal that is received from a central office terminal (COT) into a TDM downstream optical signal or to convert a TDM upstream optical signal that is received from an optical network terminal (ONT) into a WDM upstream optical signal; an error detector configured to detect an error; and a controller configured to, in response to an error being detected, transmit the WDM upstream optical signal to the COT via a first standby link or transmit the TDM downstream optical signal to the ONT via a second standby link.

Abstract: A technique for forwarding downstream packets in a GPON comprising an OLT unit having a physical PON port connected to N Optical Network Termination (ONT) units by optical fibers. The physical PON port accommodates N individual virtual GEM ports terminated with the N ONT units (ONTs) which form N:1 service. The technique comprises assigning in the physical port of the OLT unit a virtual GEM port being a shared broadcast GEM port terminated with all the N ONTs of the N:1 service. Those downstream packets applied to the physical PON port, which would otherwise be flooded—such as broadcast packets or packets having unknown destination address—will now be forwarded only via the shared broadcast GEM port.

Abstract: A method and system can propagate upstream cable modem signals and radio-frequency (RF) return video control signals over the same passive optical network (PON). The method and system can include various combinations of hardware and software to support this operation. Three exemplary embodiments of optical network terminals (ONT) of a DPON system improve performance of the system by ensuring that, in the event the upstream transmitters of two ONTs are turned on simultaneously, they will not interfere with each other. The system is designed such that in a situation of competing transmissions, the one which is received and processed by the head end out of two competing transmissions originating from a set top box and a cable modem, will be the one originating from the cable modem, which may use the DOCSIS cable modem protocol.

Abstract: An optical memory system according to example embodiments includes a plurality of memory modules, each memory module including a plurality of memory devices; a light source; a light distribution unit connected to the light source through a first optical transmission line; a plurality of second optical transmission lines connected between the light distribution unit and the plurality of memory modules; a plurality of electrical to optical converters, each connected to at least one of the second optical transmission lines; and a plurality of output optical transmission lines connected to the plurality of electrical to optical converters, each output optical transmission line for outputting an electrical to optical converted signal.

Abstract: A optical detection apparatus includes: an optical splitting unit configured to split a seed lightwave and split upward signal light generated by an optical network unit, based on the seed lightwave; a first control unit configured to control polarizations of the split seed lightwaves based on a first electrical signal; a second control unit configured to control phases of the split seed lightwaves based on a second electrical signal; an optical coupling and signal conversion unit configured to couple the seed lightwaves, of which the polarization and phase are controlled, and the split upward signal lights, convert the coupled optical signals into the first and second electrical signals, and transfer the first and second electrical signals to the first and second control units, respectively; and a signal detection unit.

Abstract: A method, apparatus and system for advertising a routing protocol message and calculating a route are provided which solve the problems that the time of connection establishment or rerouting in wavelength routing is too long and that wavelength utilization efficiency is low. The method for advertising the routing protocol message includes: obtaining node information and link information of a node, in which the node information contains port cross-connection capability information of the node, and the link information contains wavelength restriction information and wavelength status information of each link connected to the node; carrying the obtained node information and link information in a Type-Length-Value object of a routing protocol message, and advertising the routing protocol message in the network.

Abstract: Methods and apparatuses to provide wavelength locked WDM Passive Optical Networks (“PONs”) are described. A first transceiver transmits a set of optical signals in a first direction along a wavelength channel. A second transceiver transmits another set of optical signals along the same wavelength channel in another direction. The wavelength of the first transceiver is locked using an optical power of the optical signals of the second transceiver. The wavelength of the second transceiver is locked using the optical power of the optical signals of the first transceiver. A WDM MUX/De-MUX is coupled between the first transceiver and the second transceiver. An in-line gain element can be coupled to the WDM MUX/De-MUX to amplify the optical signals. The first transceiver and the second transceiver operate in a saturated gain condition.

Abstract: A burst transmission method and a receiver resetting method and apparatus in a Passive Optical Network (PON) are provided. A burst receiver resetting method in a PON includes: receiving a preamble sequence and synchronizing data; after synchronizing the data, continuing to receive the data, and matching a Burst Terminator (BT); and resetting a receiver after successfully matching the BT. Meanwhile, an apparatus for implementing the method and a corresponding burst data transmission method are provided. By using the burst receiver resetting method and apparatus in the PON and the corresponding burst transmission method at an Optical Network Unit (ONU) burst transmission end, a Reach Extender (RE) does not need to unpack upstream burst bandwidth allocation information carried in downstream data. Therefore, the complexity of the implementation of the RE is reduced, and the method is simple and effective.

Abstract: An apparatus for driving a wavelength-independent light source is provided. The apparatus includes a seed light signal generation unit configured to generate seed light signals with one or more wavelengths based on a wavelength identification signal, a wavelength light detection unit configured to detect the wavelength identification signal from the seed light signals, an extraction unit configured to extract wavelength information corresponding to the detected wavelength identification signal and extract a driving condition of a wavelength-independent light source corresponding to the extracted wavelength information, and a driving unit configured to drive the wavelength-independent light source according to the extracted driving condition.

Abstract: In accordance with the teachings of the present invention, a system and method for transmitting optical markers in a passive optical network (PON) system is provided. In a particular embodiment, a method for transmitting optical markers in a PON system includes transmitting a first optical marker signal, the first optical marker signal used to identify at least one of the first optical marker signal, an upstream wavelength corresponding to the first optical marker signal, and an optical network unit (ONU) type transmitting at the upstream wavelength corresponding to the first optical marker signal. The method also includes transmitting a second optical marker signal, the second optical marker signal used to identify at least one of the second optical marker signal, an upstream wavelength corresponding to the second optical marker signal, and an ONU type transmitting at the upstream wavelength corresponding to the second optical marker signal.

Abstract: Optical networks can comprise a branch structure with the de-multiplexing/multiplexing structure that operates to disperse a plurality of optical bands. Thus, the optical network comprises an optical network connection with a common optical channel, a plurality of de-multiplexed branch optical service connections and the de-multiplexing/multiplexing structure. In some embodiments, one optical band can be used to deliver input from a common channel to the branch node and the other optical band can carry output along the common channel from the branch node. The de-multiplexing/multiplexing element can be an arrayed waveguide grating. The AWG can have desirable architecture to efficiently provide the corresponding functions with respect to the two optical bands. Appropriate photodetectors and light sources can be associated with the AWG.

Abstract: An optical network includes a first passive optical network optical line terminal that transmits a first optical signal at a first wavelength, coupled to a first port of a first optical filter arrangement, and a second passive optical network optical line terminal that transmits a second optical signal at a second, different wavelength, coupled to a second port of the first optical filter arrangement. An optical coupler, connected between the second terminal and the second port of the first optical filter, couples optical signals at a predetermined set of wavelengths from a third optical line terminal into the second port. A passive optical distribution node connects to optical network terminations and distributes optical signals between the optical line terminals and the optical network terminations. A method of provisioning an optical network is also described.

Abstract: A node is configured to receive an instruction to establish a channel having a bandwidth that corresponds to an operating spectrum an optical fiber; obtain information that identifies a channel spacing and a pointer that identifies where, within the spectrum, to establish bandwidth allocations; identify a group of bandwidth segments based on the spectrum and the channel spacing; and generate bit words that correspond to the bandwidth allocations, where the bit words includes bits that, when set to a value, cause sets of segments to be reserved within the spectrum, and where the sets of segments identify where the bandwidth allocations begin and end, within the spectrum, relative to the pointer.

Abstract: An optical splitter for a passive optical network for telecommunication signal transmission with an optical line terminal includes a wavelength selective optical electrical converter, an AC/DC splitter, an energy reservoir and optical switches, where the splitter comprises also a data transmission processing module by which the optical switches can be controlled according to data signals transmitted from the optical line terminal.

Abstract: An optical network includes a first passive optical network optical line terminal, coupled to a first port of a first optical filter arrangement, and a second passive optical network optical line terminal, coupled to a second port of the first optical filter arrangement. An optical coupler is connected between the second passive optical network line terminal and the second port of the first optical filter arrangement. A passive optical distribution node is coupled to a third port of the first optical filter arrangement.

Abstract: A relaying method of an optical signal of a hybrid relaying apparatus in a gigabit passive optical element includes: selecting and receiving any one of a first serial electrical signal corresponding to a downlink wavelength division multiplexing-passive optical line terminal (WDM-PON OLT) optical signal and a second serial electrical signal corresponding to a downlink gigabit passive optical network optical line terminal (GPON OLT) optical signal; modulating the downlink serial electrical signal to a downlink GPON transmission convergence (GTC) frame; extracting control information for uplink transmission from the downlink GTC frame; converting the downlink GTC frame into the downlink serial electrical signal; and converting the converted serial electrical signal into an optical signal and transmitting the converted optical signal in a GPON OLT optical transceiver.

Abstract: This invention relates to provisioning wavelength-selective switches and reconfigurable optical add-drop multiplexers to minimize the bandwidth narrowing effect from the optical filters. Novel architectures and methods are disclosed that can significantly reduce bandwidth-narrowing on channels in a reconfigurable WDM network where a large number of optical filter elements are cascaded. Instead of blocking unused channels as in the prior art, unused channels are selectively provisioned depending on the state of their adjacent channels. Unused adjacent channels of an active channel are provisioned to follow the same path as the active channels. As each channels is deployed, the channel frequency is selected so as to minimize bandwidth narrowing.

Abstract: An optical network design apparatus includes a memory and a processor. The memory stores a connection limit corresponding to the number of connections between ports. The processor provisionally designs a traffic path across an optical network independently of a connection limit of an asymmetric optical hub, calculates a penalty allowance with respect to the penalty limit of the traffic path, calculates an additional penalty caused on a detour path derived by replacing a port with a replacement port in the asymmetric optical hub, and if an asymmetric optical hub is included in the detour path, generates asymmetric optical hub information about the included asymmetric optical hub, generates, based on the connection limit, penalty allowance, additional penalty, and asymmetric optical hub information, a constraint condition for adopting the traffic path satisfying the connection limit and penalty limit, and calculates the traffic path by mathematical programming under the constraint condition.

Abstract: A passive optical network system such that the power consumption can be reduced as much as possible according to the end-user traffic. An OLT uses the DBA function thereof and sequentially uses frequencies in ascending order of transmission rate in order to sequentially allocate bands to ONUs in ascending order of the requested bandwidth. At this time, a frequency to be allocated is selected so that the bandwidth allocated to each ONU is narrower than a maximum bandwidth through which transmission using the allocated wavelength is enabled. An OLT uses a grant area to specify the transmission timing of the secondary station and to inform the specified transmission timing to the secondary station. In addition, an area is set for storing information used to inform the secondary station of a new frequency to be used.

Abstract: Technologies are generally described for network traffic scheduling in a wavelength division multiplexing (WDM) passive optical network (PON). Dynamic wavelength assignment and time allocation in hybrid WDM/TDM PONs with tunable lasers as optical light generators is accomplished by mapping the scheduling into a multi-processor scheduling problem with wavelength channels as machines and ONU requests as jobs. Wavelengths may be considered as parallel identical machines. Taking laser tuning time into consideration preemptive and non-preemptive scheduling with the objective of minimizing the latest job completion time is computed employing a number of heuristic algorithms. The algorithms compute two extreme cases of zero and infinity laser tuning time, respectively. Using the results from these two extreme cases, the heuristic scheduling schemes for the case of arbitrary laser tuning time yield close average latest job completion times for both schedule types.

Abstract: Tunable resonator systems and methods for tuning resonator systems are disclosed. In one aspect, a resonator system includes an array of resonators disposed adjacent to a waveguide, at least one temperature sensor located adjacent to the array of resonators, and a resonator control electronically connected to the at least one temperature sensor. Each resonator has a resonance frequency in a resonator frequency comb and channels with frequencies in a channel frequency comb are transmitted in the waveguide. Resonance frequencies in the resonator frequency comb are to be adjusted in response to ambient temperature changes detected by the at least one temperature sensors to align the resonance frequency comb with the channel frequency comb.

Abstract: Methods and systems for providing flexible node segmentation are provided. For example, the system can be configured to delay node segmentation in the headend/hub even though the fiber node has been segmented. When a desire for node segmentation in the headend/hub arises, the receiver can be efficiently upgraded through the use of a control signal to provide a receiver output port to each sub-service area.

Abstract: A communication control method performing Discovery processing, which is a procedure at an OLT to detect an ONU newly connected, in a PON system, the method includes: a transmission-permission-signal transmitting step of transmitting, by the OLT, a transmission permission signal for discovery, which includes an individual number of an ONU that is permitted to respond and mask information for designating a match-detection target bit for the individual number; and a registration-request-signal transmitting step of comparing, by an ONU, which is not registered in the OLT, a match-detection target bit for the individual number designated in the mask information with an individual number of the ONU based on a received transmission permission signal, and when the target bit and the individual number match each other, transmitting a registration request signal to the OLT.

Abstract: Methods and apparatus are described for RFoG CPE devices with wavelength collision avoidance using local and/or remote tunability. A method includes tuning each of a plurality of optical transmitters to a plurality of non-overlapping frequency bands to avoid wavelength collisions in an upstream portion of a multipoint-to-point RFoG network where multiple optical transmitters from different RFoG CPE units transmit at the same time to a single shared optical receiver.

Abstract: Provided are a wavelength division multiplexing-passive optical network (WDM-PON) in which a reflective semiconductor optical amplifier (RSOA) is used as each optical transmitter of an optical line termination (OLT) and an optical network unit (ONU) and additional spectrum-sliced light is injected into RSOAs of each of the OLT and the ONU, and a WDM-PON that is combined with time division multiple access (TDMA) technology, by which the number of included ONUs increases and conventional TDMA ONUs can be used.

Abstract: A splitter module for a PON (passive optical network) and method of operating same. An IW (interfering wavelength) is selectively distributed and multiplexed with a downstream PON signal. The ONU (optical network unit) measures and reports performance characteristics such as BER (bit error rate). The performance reporting can be used to identify splitter ports associated with particular ONUs.

Abstract: An optical access network (OAN) system is provided. In the system, a remote radio unit (RRU) receives and sends a wireless signal and implement conversion between the wireless signal and a first frequency signal; an optical network device receives and sends the wireless signal, and implement conversion between the wireless signal and the first frequency signal and conversion between the first frequency signal and a fiber transmission signal; an optical distribution network (ODN) connected to the optical network device transmits the fiber transmission signal; an optical line terminal (OLT) device receives and sends the fiber transmission signal, and implements conversion between the fiber transmission signal and a second frequency signal, conversion between the second frequency signal and a base band signal, and conversion between the base band signal and a signal of another standard protocol.

Abstract: An approach is provided for integrating one or more fiber switches in a passive optical network. A platform generates a command signal to control a splitter hub of a passive optical network, the splitter hub being configured to communicate with a plurality of optical network terminals that respectively serve a plurality of customer premises. The splitter hub includes a fiber switch configured to provide switching between one of a plurality of input ports and one of a plurality of output ports of the splitter hub.

Abstract: The present invention is a device including a wavelength division multiplexer for multiplexing a plurality of optical carrier signals on an optical fiber. A mission processor, including an optical line terminal (OLT) is communicatively coupled to a wavelength division multiplexor branch unit via an optical fiber for generating a plurality of fiber optic branches. A plurality of fiber optic branches communicatively coupled with the wavelength division multiplexor branch unit for communicating one or more signals to at least one optical network unit, wherein the mission processor transmits a first signal having at least one downstream wavelength to the wavelength division multiplexor branch unit, and wherein the plurality of fiber optic branches are configured for transmitting a branch signals having a plurality of wavelengths.

Abstract: An interface coupled to a virtual network operations center and coupled to a data communications network having at least one optical channel. Equipment on the data communications network is identified by the interface wherein the interface coordinates and correlates communications between the I/O interfaces of a server coupled to the network so that data rates and data protocols are managed properly. The interface receives commands from and transmits commands to the data communications network and translates the commands to be further transmitted and used in the virtual network operations center coupled to the server. The data communications network is represented in a three dimensions virtual world in the virtual network operations center so that events on the network can be represented in real-time in the virtual network operations center.

Abstract: A device for routing an upstream signal from a two-way digital output to an existing hybrid fiber coax network. A first path includes an input for receiving downstream optical signals associated with data and a two-way digital port for communicating the data of the downstream optical signals to a subscriber. A second path includes a hybrid fiber coax input and a two-way hybrid fiber coax port for communicating with the subscriber. A filter is disposed in the first path for routing an upstream signal from the subscriber at the two-way digital port to the second path for forwarding upstream via the hybrid fiber coax input.

Abstract: A system for serving N optical communication lines by a redundant set of modules in an optical network; where the set of modules comprises N>1 main modules and one backup module, N optical splitters, 2N fiber connections and a control means. In the system, each of the N optical splitters is connected to two different modules of the set by two respective fiber connections out of the 2N connections, while each of the N optical splitters is also coupled to one of the N optical communication lines. The arrangement is such that the control means selectively activates/inactivates any of the fiber connections for respectively enabling/blocking transfer of data there-along; the control means thus ensures that each specific line of the N optical communication lines is always served by either one or another of two different modules.

Abstract: Various example embodiments are disclosed. According to an example embodiment, a method may include determining that a transmission of a data signal over a path of a wavelength division multiplexed (WDM) optical network using a group of optical subcarriers is not optically feasible; determining that the transmission of the data signal over the path using a subset of the group of optical subcarriers is optically feasible; activating subcarriers for the subset of optical carriers while deactivating one or more optical subcarriers of the group, at least one deactivated subcarrier provided between at least two activated subcarriers of the group; and transmitting the data signal over at least a portion of the path using the activated subcarriers of the group.

Abstract: According to one embodiment, a system for transmitting an optical signal comprises a traffic distribution circuit configured to distribute traffic to a plurality of wavelength division multiplexer (WDM) modules. The system further comprises a first WDM module and a second WDM module. The first and second WDM modules each comprise a plurality of tunable optical transmitters, with each transmitter associated with a different wavelength band of a plurality of wavelength bands. Each transmitter in the first and second WDM modules is also tuned to transmit optical signals in channels included within the associated wavelength band of the transmitter. The first and second WDM modules each comprise a multiplexer configured to combine the optical signals transmitted from the plurality of transmitters into optical signals. The system further comprises a cyclic multiplexer configured to combine the optical signals from the first and second WDM modules into an optical output signal.