94 results about "Wdm optical networks" patented technology

The invention relates to a method for auto-configuring a wavelength selective switch (WSS) device having an output port and a plurality of input ports and coupled to a WSS controller. When connected to a WDM optical network, the WSS controller is programmed to utilize one or more optical channel monitors (OCM) coupled to the input and/or output ports to detect which of the wavelengths are present at the input ports. Wavelengths that are not detected on any input port are blocked by the WSS. Any wavelength detected as present at one and only one input port is switched by the WSS to the output port. If a wavelength is detected at two or more input ports, it is either blocked by the WSS at each of the input ports until user intervention, or is blocked at all but one of the input ports as defined by assigned port priorities.

The invention provides a synthesis persuasion business method WDM OTN. Wherein, building a persuasion chart model combined with virtual topological design, rout and wavelength allocation problem, calculating on the chart to find out proper persuasion path. For business request, using built optical link for persuasion. This invention uses dynamic regulation link weight to regulate dynamically whole network link weight at any moment to balance load, and saves optical transceiver resources to reduce cost.

The invention discloses a passive optical network (PON) and a signal transmission method thereof. The PON comprises a wavelength selection coupler, an optical splitter, an array waveguide grating (AWG) and a plurality of wavelength selection routers, wherein, the wavelength selection routers couple a downlink signal from a time division multiplexing optical line terminal (TDM-OLT) of the optical splitter and a downlink signal from a wavelength division multiplexing optical line terminal (WDM-OLT) of the AWG and then transmit the coupled signals to branch optical fibers connected with the wavelength selection routers, and transmit an uplink signal in a branch optical fiber connected with a WDM optical network unit (WDM-ONU ) to the AWG and then transmit an uplink signal in a branch optical fiber connected with a TDM-ONU to the optical splitter. The invention enhances network compatibility and improves user experiences.

A communications network has a plurality of nodes interconnected by an optical transmission medium. The transmission medium is capable of a carrying a plurality of wavelengths organized into bands. A filter at each node for drops a band associated therewith and passively forwards other bands through the transmission medium. A device is provided at each node for adding a band to the transmission medium. Communication can be established directly between a pair of nodes in the network sharing a common band without the active intervention of any intervening node. This allows the network to be protocol independent. Also, the low losses incurred by the passive filters permit relatively long path lengths without optical amplification.

An economical wavelength-division-multiplexed passive optical network (WDM-PON) system is realized by directly modulating a wavelength-seeded light source to transmit upstream or downstream data, without using an expensive external modulator. A multiplexed signal having the same wavelength as the waveguide grating is generated and used to control the temperature of the waveguide grating and adjust the wavelength of a wavelength-division-multiplexed signal routed to a transfer link. The wavelength selectivity and stabilization of each light source are not required. Since upstream and downstream signals can be multiplexed and demultiplexed concurrently by each waveguide grating located in the central office and the remote node, it is possible to reduce the number of waveguide gratings used in a WDM optical network. In addition, upstream and downstream signals can be transmitted concurrently using a single-strand transfer optical fiber, thereby realizing an economical and efficient WDM-PON.

A network planning tool and method for configuring a connection-oriented packet network over a WDM optical network without an optical control layer, such as a SONET/SDH layer. The optical network includes a plurality of optical fibers interconnected through nodes and the connection-oriented packet network, such an Ethernet network, MPLS network, or pseudowire network, includes two or more terminal devices. The method and tool function by building an association between the components of the physical layer, such as the optical fiber, and their geographic location or path. The connection-oriented packet network is configured by building multi-link trunks (MLTs) between terminal devices, where the MLTs are built by aggregating lightpaths that traverse distinctive geographic paths. The MLTs are planned and configured through aggregating lightpaths that traverse incongruent sets of photonic elements. A predetermined target for resiliency to physical failure events may determine the degree of congruence allowed between the sets of photonic elements associated with lightpaths in the same MLT.

The invention provides a utility-based interlayer coordination method in a WDM (Wavelength Division Multiplexing) optical network, which comprises the following steps of: calculating the utilization rate of resources protected by a WDM layer; calculating the failure recovery utility of a light path of an IP (Internet Protocol) layer; and comparing the failure recovery utility of the WDM layer with the failure recovery utility of the IP layer. When the method is adopted, a failure recovery sequence of determining respective layers can be realized in case of a failure, and a utility-based interlayer coordination mechanism used for balancing the failure recovery time and the utilization rate of the protected resources is designed to be used for dynamically assessing and deciding the failure recovery in comprehensive consideration of the failure recovery time and the utilization rate of the protected resources; thus, the advantages of the recovery of the WDM layer and the recovery of the IP layer can be better utilized, the failure recovery time is reduced, and the utilization rate of the protected resources is increased.

The invention provides a multicasting protection method in a WDM optical network, which comprises the steps that: A. the working path starting from a source node to a destination node is obtained; B. the protection path to which the working path corresponds is obtained; and C. step A and step B are followed again till the working paths starting from the source node to all the destination nodes and the corresponding protection paths are obtained. In the invention, the protection path to which the working path corresponds is obtained immediately after each working path is obtained, thus avoiding the condition that all the working paths first construct a working tree with occupying more network resources and thus the protection tree can not be successfully constructed from occurring. Therefore, the adoption of the invention can lower the probability of the network congestion.

The invention relates to a protection method with a plurality of service grades for multiple faults in WDM networks, pertaining to the technical field of optical network communication. The method comprises the steps as follows: step one: connections of different grades are established for service requests arrived, that is, working accesses and accesses for protection are established; step two: for service connections conveying data in the networks, when failed links occur, the service grade is judged, different protection methods are executed to services of different grades, and enhanced recovery is executed to the service of the highest grade. The method of the invention meets the requirements for different protections raised by users in case of multilink faults in the WDM optical networks. EDSP takes into consideration of an enhanced recovery mechanism for load balancing, protection of resource sharing and resource recycling, so as to improve resource utilization rate and reduce blocking probability; effective multiple faults protection is also provided, and the requirement for services of diamond grade (highly reliable protection for multiple faults (three faults and more)), platinum grade (single fault being 100 percent protected) and economic grade (no protection) are met.

A survivability business dredging method based on interlayer message routing belongs to the technical field of communication network, and relates to an optical network business dredging technique and resource allocation method. The survivability business dredging method comprises the following steps: step1: constructing a virtual topological network according to a physical topological network structure; step 2: executing routing and resource allocation to each service in service aggregate in the virtual topological network; step 3: modularizing optical path; and step 4: allocating resource for physical chain in the physical topological network according to the optical path modularization result obtained in the step 3. According to the invention, at the state the connection state and service aggregate between the network node and the node is known, the routing is searched for service and resource is collocated based on the interlayer information. The usage of total resource in the physical network is reduced as possible. Furthermore the resource collocation speed is greatly increased. The invention is suitable for WDM optical network and is also suitable for two-layer and multi-layer network with different service granularities of the upper layer and the lower layer, for example: IP/MPLS over WDM network, two-layer SDH network, etc.

The invention discloses an automatic configuration method of a physical device in a WDM (Wavelength Division Multiplexing) optical-fiber network, comprising the following steps of: A10, collecting network parameters of the WDM optical-fiber network and constructing a network software model; A20, setting parameters of each physical device in the WDM optical-fiber network into each physical device parameter bank; A30, setting the configuration rule of the physical device according to the maximum wavelength division number of a wavelength division network, OSNR (Optical Signal to Noise Ratio) limitation and dispersion limitation; and A40, extracting the device parameters from each physical device parameter configuration table respectively and sequentially configuring all the physical devices in the WDM optical-fiber network according to the configuration rule. In the invention, a complicated WDM network can be automatically and quickly configured, concerned data of OSNR values of each multiplex section, chromatic dispersion values, and the like in engineering can be quickly output, the effectivity of network device configuration can be quickly checked, and device configuration defects caused by data errors in artificial configuration can be avoided.

The invention discloses an ROADM node, an optical wavelength correction frequency shifter and an implementation method. The wavelength correction frequency shifter comprises a sawtooth wave electric signal generator and an electro-optic phase modulator, wherein the sawtooth wave electric signal generator produces continuous sawtooth wave electric signals with the repetition frequency of F, which serve as driving electric signals, and the electro-optic phase modulator loads driving electric signals to conduct frequency shift delta fi on the central wavelength of input optical signals, so that the central wavelength lambada i of input optical signals is close to the expected central wavelength lambada i-1, and c represents the velocity of light. According to the ROADM node, the optical wavelength correction frequency shifter and the implementation method, the central wavelength of input optical signals is close to the designed central wavelength of an ROADM through correction of the central wavelength of input optical signals, so that the effective bandwidth loss of the ROADM, which is caused by the multistage filtering cascaded filtering function, is reduced, an all-optical method is used for correcting the wavelength of optical signals, and the implementation method is applicable to ROADM nodes of any wavelength multiplexing wavelength division multiplex (WDM) optical networks of various transmission rates.

The invention provides a persuasion method of a self-adaptive dynamic multicast service and a node system provided with the persuasion method of the self-adaptive dynamic multicast service, and belongs to the technical field of network communication. The node system comprises an optical layer and an electric domain layer. The persuasion method of the node system includes that a plurality of methods for a transmission service in a wavelength division multiplex (WDM) optical network are firstly analyzed, and two multicast service persuasion strategies including a node transceiver number minimum use strategy and a node persuasion port number minimum use strategy are proposed according to different optimization objectives. Due to the fact that network resource changes at different moments, a threshold value parameter is set to judge which resource is rare resource at the moment, and therefore the transmission of a new service is accomplished through a suitable selection of a persuasion strategy. The self-adaptive dynamic service persuasion method is capable of effectively solving the problem of dynamic multicast service persuasion in the WDM optical network, substantially improving the service persuasion performance of the WDM optical network, reducing service blocking rate, and increasing network throughput.

The invention provides a multicast-sharing and multilayer protection method based on subtrees in a WDM (wavelength division multiplexer) optical network, belonging to the technical field of network communications. The method comprises the steps of: establishing a working multicast forest, establishing a protection multicast forest, protecting a WDM layer and leaving services. In the method, under the premise of considering single-link faults, a multicast-sharing protection method is constructed on the basis of the subtrees, a subtree-protecting resource sharing strategy, a light-path resource sharing strategy and a wavelength link protecting resource sharing strategy are adopted according to differences of shared grain sizes, so that the quantity of damaged services when a physical link generates faults is reduced, the application range of the traditional multicast-sharing and multilayer protection method can be expanded, multiple constraining conditions are considered when multilayer protection is carried out, and the multicast-sharing and multilayer protection method is provided under multiple strategies.

The invention discloses a method for simulating optical network of wave division multiplex (WDM) by computer. The computer executes following steps. The computer provides at least one main interface that includes a section for drawing layout of optical network, a toolbar section. The toolbar section provides selectable operations; system planning, performance simulation, simulaing algorithm of allocating route or wave length. Said function of system planning is that based on user's planning target, the system planning generates a topological graph of optical network on the said drawing section. The optical network on the drawing section is carried out a simulation by function of performance simulating. Based on physical toplogy and logical topology, the algorithm of allocating route or wavelength selects suitable route and allocates optimized wavelength and evaluates the algorithm for dynamic business.

Disclosed is an apparatus for monitoring an optical signal-to-noise ratio in a WDM optical network. The apparatus includes an orthogonal polarization component module for receiving an optical signal and outputting it after removing a signal component thereof at a specific frequency band; and calculation means for measuring both average signal and noise component intensity of the optical signal outputted from the orthogonal polarization component module. By removing a signal component at a specific frequency bandwidth and passing only a noise component through, it is possible to easily measure the noise intensity within a signal bandwidth that cannot be measured in general. A frequency band is set within a signal bandwidth, and the signal intensity is minimized at the set frequency band, so that it is possible to measure the optical signal-to-noise ratio even for a signal whose amplified spontaneous emission noise spectrum is not flat, irrespective of the signal pattern length.

A wavelength division multiplexed (WDM) optical network includes a plurality of optical transmitters, each optical transmitter generating a data signal sent over a respective one of a plurality of signal channels, the plurality of signal channels being divided into a number of sub-bands where each sub-band includes at least two signal channels, and a plurality of substitute signal transmitters, the number of substitute signal transmitters being equal to the number of sub-bands, each substitute signal transmitter generating a substitute signal which provides loading in a corresponding sub-band. The WDM optical network also includes a combining circuit which combines the data signals output from the plurality of optical transmitters and the substitute signals output from the plurality of substitute signal transmitters into a WDM signal, and an optical transmission fiber which receives the WDM signal from the combining circuit.