152 results about "Wavelength allocation" patented technology

In a WDM type PON system, each ONU comprises an optical transmitter capable to transmit optical signals with variable wavelengths, an optical signal receiving filter variable its receiving wavelength, and a control unit. An OLT selects in response to a wavelength allocation request from each ONU, a transmitting wavelength and a receiving wavelength out of currently free wavelengths and allocates these wavelengths to the requester ONT. The control unit of the ONU switches the transmitting wavelength of the optical transmitter and the receiving wavelength of the optical signal receiving filter to the wavelengths specified in a response message from the OLT and starts data communication.

There is provided a method in a wavelength convertible flexible optical wavelength-division multiplexing (WC-FWDM) network. The network has a plurality of optical nodes interconnected by a plurality of optical fibers. The network is for providing an overall spectrum divisible into a set of consecutive wavelength slots. At least one optical node has at least one wavelength converter for wavelength conversion. The method includes determining a channel route through the network commencing at a source node and ceasing at a destination node. The determined channel route is selectively tunable responsive to selected ones of a plurality of routing methods. The routing methods are so selected responsive to a routing policy having one or more objectives of minimization of channel blocking, minimization of a number of wavelength converters used in the network, and minimization of physical distance traversed by a channel, and minimization of operating wavelengths of a channel.

The present provides a method of dynamically managing multicast groups and allocating multicast service wavelengths for the highest channel efficiency. According to the present invention, the share indices of wavelengths of all multicast service groups, which employ broadcasting wavelengths and data wavelengths, are periodically ascertained on the basis of IGMP snooping-based technology in a WDM-PON. Based on the ascertainment results, if the channel share index of the group that employs the broadcasting wavelength is smaller than the channel share index of the group that employs the data wavelength, the share index of the wavelength of the multicast group that employs the broadcasting wavelength is maximized by dynamically changing allocation of the wavelength of the multicast group, so that a maximum multicast service can be provided within limited resources.

A method includes determining a line rate selection for a flexible optical wavelength-division-multiplexing WDM network, determining a traffic routing in said network, and determining simultaneously a channel routing, wavelength assignment and spectrum allocation in said network based on an auxiliary graph.

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 wavelength allocation method of a WDM-PON system, which comprises the following steps: extending an OAM frame, adding wavelength management information and defining a special wavelength for sending control messages; carrying out the interaction of the control messages through wavelength management units in an OLT and an ONU and allocating upstream wavelengths and downstream wavelengths used for service allocation communication; and realizing data communication between the OLT and the ONU according to the successfully allocated upstream wavelengths and the downstream wavelengths used for the service communication. The method adds the wavelength management information into an Organization specific information TLV field by an INFO message in a discovery process of IEEE 802.3ah OAM, and other fields in the message are not modified, thus the method has clear and simple processing and flexible configuration. Hardware units in a system donot need to be modified, and processing is carried out completely depending on a software unit, thus the cost is lower. The speed and the accuracy of the data transmission of the system are greatly improved, and meanwhile, the complexity of the network operation and maintenance of the system is also reduced.

A communication device which communicates with a plurality of subscriber communication devices using optical signals of a plurality of wavelengths, includes: a traffic monitoring section for monitoring a downstream traffic volume of a downstream signal destined for each of the plurality of subscriber communication devices; and a resource allocating section for allocating a different one of a predetermined number of wavelength resources to each of groups which includes at least one downstream signal grouped according to a predetermined wavelength allocation rule based on its downstream traffic volume.

In a WDM type PON system, each ONU comprises an optical transmitter capable to transmit optical signals with variable wavelengths, an optical signal receiving filter variable its receiving wavelength, and a control unit. An OLT selects in response to a wavelength allocation request from each ONU, a transmitting wavelength and a receiving wavelength out of currently free wavelengths and allocates these wavelengths to the requester ONT. The control unit of the ONU switches the transmitting wavelength of the optical transmitter and the receiving wavelength of the optical signal receiving filter to the wavelengths specified in a response message from the OLT and starts data communication.

An add / drop arrangement using broadband optical couplers provides a low-loss, highly flexible add / drop capability for survivable wavelength division multiplexed (WDM) ring networks. At each node in the ring having the broadband optical coupler-based add / drop element, a portion of optical signal power of the entire WDM signal (i.e., all optical channels) is tapped off so that one or more optical channels of particular wavelengths can be dropped at the node. Information (e.g., data) to be added at the node is supplied in an optical channel that is added to the WDM signal via the broadband coupler. Because the add / drop element uses a broadband coupler, another portion of optical signal power of the WDM signal, including any added optical channels, passes through the node onto the ring. Depending on the specific ring topology being used with the broadband coupler-based add / drop arrangement, additional wavelength assignment and handling measures may be required. For example, certain ring topologies may experience interference between optical channels of particular wavelengths due to possible re-circulation of these optical channels beyond the add and drop nodes (e.g., after an optical channel passes its destination node). According to one illustrative embodiment, a node is equipped to perform wavelength conversion and / or wavelength suppression to prevent undesirable re-circulation of optical channels.

A contrivance, if a WDM signal state changes, is to improve an optical transmission quality by compensating gain flatness. A first excitation control unit sets a first optical pumping light source unit to emit excitation power needed to get the same amplifying operating level of a first amplifying medium as at the time of a maximum wavelength count when allocating wavelengths after a change in wavelength count at an equal interval in a wavelength range. A wavelength allocation bias estimation unit compares a present monitor value of optical power after outputting of a gain equalizer 13 with wavelength equi-allocation power associated with the recognized wavelength count, and thus estimates a wavelength allocation bias occurred as a concomitant of the change in the wavelength count. A primary gradient calculation unit obtains a primary gradient quantity defines as a gain deviation from the wavelength allocation bias. A second excitation control unit sets, in a second optical pumping light source unit, the excitation power needed to cancel the primary gradient quantity. An attenuation quantity control unit controls a variable optical attenuator to fix a gain by compensating an amount of change in the sum of gains.

Techniques are disclosed for generating a hitless migration plan to optimal state, given an optimal routing and wavelength assignment for demands. For example, a technique for use in performing a circuit transition in accordance with an optical ring-based network comprises obtaining a first (e.g., initial) circuit layout and a second (e.g., final) circuit layout for a given set of demands to be routed on the optical ring-based network. The technique then comprises calculating a transition sequence plan useable to transition the network from the first circuit layout to the second circuit layout such that substantially no network service disruption occurs due to the circuit transition. The transition sequence plan is calculated by determining a minimum set of circuits that when moved from first positions in the first circuit layout result in a feasible transition sequence for remaining circuits in the first circuit layout. Wavelength equivalence and demand equivalence properties may be applied individually or jointly.

The present invention relates to an optical wavelength channel connection recognition control method. In an optical transmission system, a transmission section outputs plural monochromatic-wavelength lights individually, a first allocation section allocates a wavelength of a monochromatic-wavelength light based on a power of the monochromatic-wavelength light individually outputted from the transmission section from among the plural monochromatic-wavelength lights, a notification section issues a notification of wavelength information of the monochromatic-wavelength lights allocated by the first allocation section to the transmission section, and a first control section controls wavelengths of the monochromatic-wavelength lights to be outputted from the transmission section based on the wavelength information of the notification issued from the notification section. With this configuration, the optical transmission system becomes automated to significantly improve a convenience in channel allocation thereby to achieve simplification and improvement in efficiency of a cross connection function and reduction of a cost.

The invention discloses a method and device for rapidly measuring sidewall appearance of a micro-nano deep groove structure, which can simultaneously and rapidly measure the parameters of the sidewall appearance of the micro-nano deep groove structure, such as line width, groove depth, sidewall angle, sidewall roughness and the like. The method comprises the steps of: projecting elliptical polarized lights, which is obtained by polarizing light beams with the wavelengths ranging from near infrared waveband to middle infrared waveband, onto the surface of a structure to be measured; collecting zero-level diffraction signals on the surface of the structure to be measured, and calculating to obtain a measured infrared spectroscopic ellipsometry of the micro-nano deep groove structure; calculating theoretical spectroscopic ellipsometries in the near infrared waveband and the middle infrared waveband respectively by using a wavelength allocation modeling method, matching the theoretical spectroscopic ellipsometries with the infrared spectroscopic ellipsometry measured in the experiment by using a stepwise spectral inversion method, and sequentially extracting the groove structure parameter and the roughness parameter. The device comprises an infrared light source, first, second, third and fourth off-axis parabolic mirrors, a Michelson's interferometer, a planar reflector, a polarizer, a sample bench, an analyzer, a detector and a computer; and the method is a noncontact, nondestructive low-cost method for rapidly measuring the sidewall appearance.

A method includes determining a line rate selection for a flexible optical wavelength-division-multiplexing WDM network, determining a traffic routing in said network, and determining simultaneously a channel routing, wavelength assignment and spectrum allocation in said network based on an auxiliary graph.

The embodiment of the invention discloses a wavelength selection method, a wavelength selection device and a wavelength selection system, relates to the field of optical integration and solves the technical problem that the conventional equipment is greatly modified in the process of transmitting common public radio interface (CPRI) optical signals through an optical distribution network (ODN) inthe prior art. The method in the embodiment of the invention comprises the following steps of: configuring the receiving wavelength of an optical module as a first uplink wavelength according to a wavelength allocation list; acquiring uplink detection information for indicating whether an uplink optical signal reflected by a partial reflector is detected on the first uplink wavelength; if the acquired uplink detection information indicates that the reflected uplink optical signal is not detected, configuring the receiving wavelength of the optical module as a corresponding first downlink wavelength; acquiring downlink detection information; and if the acquired downlink detection information indicates that a downlink optical signal is detected, configuring the transmitting wavelength of the optical module as the first uplink wavelength. The embodiment of the invention is mainly applied to wavelength division multiplexing (WDM) scenes.

The invention discloses a system for supporting wavelength management in a passive optical network (PON). The system comprises an optical line terminal (OLT) configured for wavelength assignment for optical network unit (ONU) communications based on a wavelength tunability capability; and an ONU coupled to the OLT and configured to send the wavelength tunability capability to the OLT, wherein the wavelength assignment and the wavelength tunability capability are sent in media access control (MAC) messages. Also disclosed is an apparatus of an OLT for supporting wavelength management. The apparatus comprises one or more component configured to couple to an ONU and exchange a wavelength assignment for transmission with the ONU based on a wavelength tunability of the ONU, wherein the wavelength indication and the wavelength tunability are exchanged via MAC layer frames.

The present invention relates to a technique suitable for the enhancement of efficiency of wavelength allocation in an optical network. A transmission capability for each of a plurality of wavelengths available in the optical network is calculated to allocate, to a recommendation optical transmission path in the optical network for a traffic demand from the external, a wavelength having a transmission capability corresponding to a total optics transmission distance of the recommendation optical transmission path on the basis of a result of the calculation. This enables considerably reducing the number of optical repeaters to be disposed, each of which has an electrical signal regeneration function in the optical network, thereby reducing the number of devices, dissipation power, installation area and others in the optical network.

When dynamic wavelength bandwidth allocation using a fixed cycle such as a multiple request method is realized in wavelength tunable WDM / TDM-PON, there is required a wavelength switching method that can suppress a transmission delay of an uplink signal and an increase in burst characteristics, that is, suppress an increase in an allocation cycle to a minimum.An ONU requests a bandwidth of an uplink signal, and in accordance with this, an OLT calculates a time when the OLT transmits the uplink signal and a transmission duration time and performs an instruction, and a DBA cycle in which the ONU transmits the uplink signal in accordance with the instruction and a dynamic wavelength allocation cycle in which the OLT instructs wavelength switching, and the ONU switches the wavelength and belongs to a different LC are separated. While the ONU switches the wavelength, the DBA cycles can be performed plural times in the ONU whose wavelength is not switched, the switching of the wavelength is confirmed after the wavelength has been switched, and then DBA operation is performed at the switched wavelength.

The invention discloses a static routing and wavelength allocation method based on layered graphs, which relates to the technical field of optical communication. In view of the characteristics of high complexity, requirements for static RWA problem splitting and the like in the existing static RWA algorithm, the method of the invention comprises the following steps: generating a layered graph model matrix for network topology; generating a service request set matrix D for network randomly, and selecting a single service from the generated service request set matrix; and carrying out routing and wavelength allocation operation on the service selected from the service request set matrix D on the generated layered graph model, thereby determining the optical channel matrix and the wavelength value. The invention can avoid splitting the static RWA problem and effectively save network resources. The invention can also evaluate the performance of various related algorithms to obtain multiple performance parameters of the algorithms, and find out the optimal solution by performance comparison, thereby realizing the preset optimization goal of saving network resources, such as wavelength, optical fiber and the like.

The invention discloses an allocation method for downlink wavelength in a shared multi-wavelength WDM-PON (Wavelength Division Multiplexing-Public Data Net Works) system, which belongs to the field of optical communication technology. The shared multi-wavelength WDM-PON system comprises a optical line terminal (OLT) and a plurality of optical network units connected with the OTL through optical fiber, wherein each of the optical network units is allocated with a dedicated wavelength; each unit optical network unit can use the dedicated wavelength thereof and at least one sharing wavelength to receive downlink data; service is pre-divided into a high priority and a low priority; wavelength allocation is based on the principle of giving priority to the dedicated wavelength when new service packet comes; the OLT periodically polls the queue of each wavelength and reallocates the wavelength according to the queue of each wavelength; and the wavelength reallocation is based on the principle of the high priority service preempting the dedicated wavelength. According to the allocation method for downlink wavelength in the shared multi-wavelength WDM-PON provided by the invention, a wavelength reallocation mechanism is introduced to guarantee QoS (Quality of Service) of different service so as to better adapt to demand diversity of different user service.

The invention discloses a large request first-fair excess (LRF-FE) allocation dynamic wave length bandwidth allocation method which is suitable for a time-and wavelength-division multiplexed passive optical network (TWDM-PON), and belongs to the technical field of optical access networks. According to the method, optical network units (ONU) transmit request bandwidths to an optical line terminal (OLT); the OLT adopts an LRF-FE algorithm to authorize all the ONUs, i.e. all the ONUs are ordered from large to small according to the request, wavelengths which are firstly not occupied are sequentially allocated to the ONUs according to the sequence, and available wavelength communication channels and initial using times of the ONUs are designated; and the OLT allocates the available bandwidths to the ONUs according to an excess quota bandwidth fair excess (FE) algorithm and designates the transmission data window for the ONUs. After an LRF wavelength allocation algorithm is applied, time fragments on wavelength communication channels can be reduced, wavelength resources can be effectively utilized, the time delay of a system can be reduced, and the resource utilization rate of the system is improved; and after an FE bandwidth allocation algorithm is applied, the system can fairly allocate resources, so that the fairness of the ONUs is realized. Consequently, an LRF-FE is an efficient and fair dynamic wavelength and bandwidth allocation algorithm.

The invention discloses a wavelength allocation method for quantum signal and classical optical signal common-optical fiber transmission. In the method, a wide difference of signal power between a quantum signal and a classical optical signal is considered, the method aims at fiber nonlinear effects (mainly comprising four-wave mixing and raman scattering) and crosstalk effect in the common-optical fiber transmission of the signals, and the wavelength allocation method including interleaved channels, unequalled all channel frequency spaces and maximum frequency space between adjacent quantum channels and synchronous optical channels is designed. The design of the method is simple, compared with a wavelength division multiplexing system with equal frequency space, under a premise of the ensured same bandwidth availability ratio, an influence from four-wave mixing to the quantum signal and the classical optical signal can be completely avoided, interference from raman scattering and crosstalk to the quantum signal can be reduced, a farther secure transmission distance can be realized, and system performance can be improved.

The method of placing regenerators along a trail connecting a source network node with a destination network node of an automatically switched optical network first identifies N tentative regeneration sites and n+1 optical paths along the trail. Wavelengths are assigned to each optical path, and the performance of the trail is assessed based on regenerator placement data and wavelength assignment data.

The embodiment of the invention discloses a wavelength allocation method of a wavelength division multiplexing passive optical network, comprising the following steps of: acquiring wavelength information which corresponds to an available wavelength in the network, and carrying the wavelength information to a VLAN (Virtual Local Area Network) domain of a downlink Ethernet message; and sending the downlink Ethernet message to an optical network unit so that the optical network unit sends uplink data by adopting a wavelength which corresponds to the wavelength information. The wavelength allocation method provided by the embodiment of the invention is used for sending the wavelength information to the optical network unit by utilizing the downlink Ethernet message, thereby realizing the automatic adaptation of the wavelength of the passive optical network and being convenient to maintain. The embodiment of the invention also further discloses wavelength division multiplexing passive optical network system and equipment.

Provided is an OLT including a wavelength splitter that splits all upstream optical signals with different wavelengths received from at least one ONU according to wavelength, at least one receiver that receive the optical signals split by the wavelength splitter according to wavelength, a wavelength selector that allocates an upstream transmission wavelength of the at least one ONU, and a transmitter that transmits wavelength allocation information allocated by the wavelength selector to the at least one ONU.

The invention discloses a time and wavelength division multiplexed passive optical network resource allocation mechanism based on flow prediction and belongs to the technical field of passive optical networks in access networks. According to the mechanism, when an OLT authorizes a bandwidth request of an ONU, wavelength allocation is conducted with the earliest free wavelength priority algorithm firstly, then allocation of time slot bandwidths on each wavelength is conducted with the linear prediction algorithm, and prediction bandwidth and the required bandwidth of an uplink REPORT frame of the ONU are authorized to the ONU together. In this way, data newly reaching the ONU can be considered as much as possible in the whole request-authorization process, so that the data are sent in the same period instead of waiting to be sent in the next period, and then packet delay can be reduced as much as possible.

A bidirectional optical transceiver is disclosed. The transceiver comprises an optical fiber which is adapted to input / output optical signals and has a slant surface polished with an angle, a substrate having a groove formed on its upper portion to position the optical fiber therein, a wavelength distributor filter inserted into the substrate with a slant substantially matching the angle in the optical fiber, a photodiode positioned on the substrate to receive optical signals, a TO-Can having a laser diode that is positioned in a location opposite to the optical fiber to transmit optical signals, and a single housing adapted to mount the optical fiber, the substrate, and the TO-Can thereon.

The invention provides a WDM-OFDM-PON three dimensional bandwidth distribution method and a system. The method comprises steps of determining a distribution order of each ONU, determining the wavelength of each ONU, performing wavelength allocation on the ONU in order to make the load difference between wavelength adjustment overhead and the wavelength be the smallest, performing frequency distribution on the ONU in each wavelength to make the load difference of each frequency channel in the wavelength and the spectrum fragment to be the smallest. The invention combines wavelength division multiplexing, frequency division multiplexing and time division multiplexing, meets the characteristics of all priorities of businesses, and makes the bandwidth change flexibly along with the network flow. The invention also has capabilities of high spectrum utilization, anti-interference between codes and anti-fading, which greatly improves the transmission speed.

The present invention relates to a wavelength allocation method and a device. The wavelength allocation method comprises that an optical line terminal receives the operating parameter values transmitted by a current on-line optical network unit, the operational parameter values are N operating parameter values of a wavelength tuning area when the current on-line optical network unit utilizes N available wavelengths, the N operating parameter values correspond to N available wavelengths (N > 0); a wavelength is allocated to the current on-line optical network unit according to the operating parameter value; and instruction information is transmitted to the current on-line optical network unit, and the instruction information comprises the wavelength allocated to the current on-line optical network unit.

Described is a method for managing the traffic protection in OMS-SPRING networks and allowing the wavelength allocation change in the traffic transit nodes. The method of managing the traffic protection in an OMS-SPRING network should a span of the path fail is characterized in that it comprises the steps of providing a wavelength interchange mechanism; performing a ring Span Switch action by the OMS-SP mechanism; and re-routing the wavelength interchanged path on the protecting wavelength corresponding to the working wavelength of the span affected by a failure.