41 results about "Photonic network" patented technology

A network arrangement for aggregation of groups of tunable sources in a photonic network is disclosed. The network arrangement includes transmit edge elements having a plurality of tunable optical transmitters, an optical switch and a cyclic optical multiplexer, and receive edge elements having optical demultiplexers, optical switches and a plurality of optical receivers. A variety of arrangements are disclosed including protected and unprotected network architectures. The network arrangement disclosed is particularly useful for overcoming the problem of scaling a photonic network.

The present invention relates to a hybrid photonic crystal fiber, into the core of which a functional material is injected. The hybrid photonic crystal fiber of the present invention comprises: a central hole having a diameter of 4 to 15 μm extending in the longitudinal direction; an inner cladding also formed in the longitudinal direction outside the central hole, having a hexagonal arrangement of air holes, each of which has a diameter of 2 to 5 μm and a lattice constant of 4.5 to 7 μm; an annular outer cladding surrounding the outer surface of the inner cladding; and a core formed by filling a functional material in some of the air holes including the central hole. According to the present invention, changes in the state, i.e. the liquid, liquid-crystal, or biofluid states, of the functional material that fills the core that has a variety of shapes may enable the modulation of light intensity, wavelength, phase, and polarization, and thus enable various photonic networks to be produced. The hybrid photonic crystal fiber of the present invention may serve as various optical sensors capable of sensing changes in refractive index caused by external stresses such as temperature and pressure. The hybrid photonic crystal fiber of the present invention may be used as a light source for a fluorescent dye laser for a visible ray zone using fluorescent dye, or for an ultra-wideband laser of 700 nm or higher using high nonlinear liquid.

An agile transparent network with a trail routing and switching (also called “engineering”) mechanism is provided that enables efficient use of regenerators and wavelengths available in the network, while maintaining a very efficient time-to-service. The trail engineering mechanism allows fast, automatic establishment of new connections based on the current network architecture, connectivity and loading and also on conditions in the connection request. Selection of regenerator sites and of the wavelengths used on each regenerator segment is performed with optimal use of current network resources, while ensuring that the quality of the selected trail is adequate for the respective call. The mechanism provides for both distance and performance balancing, and it optimizes the network response time.

A photonic network includes a plurality of nodes each supporting add and drop of at least Y wavelengths, a plurality of optical links interconnecting the plurality of nodes, the plurality of optical links support up to X wavelengths and Y≦X, an optical routing protocol configured to compute a loop-free path through the plurality of nodes on the plurality of links, the loop-free path is computed for one of the X wavelengths or a group of the X wavelengths using routing constructs adapted to a photonic domain, and optical components at each of the plurality of nodes configured to selectively block at least one of the X wavelengths based on the computed loop-free path. A photonic routing method and photonic node are also disclosed.

A WDM optical network comprising a plurality of nodes has a first apparatus for optical analysis at the site of a first optical amplifier upstream of the first node, a second apparatus for optical analysis at the site of a second optical amplifier at the downstream output of the first node, and a third apparatus for optical analysis at the site of a third optical amplifier further downstream of the first node, where knowledge of the optical sin to noise ratio (OSNR) is desired. The first, second and third apparatus are for measuring the signal level at frequencies both at and in-between the channel frequencies. The signal levels at the channel frequencies and between the channel frequencies at the first, second and third apparatus are used to derive the OSNR at the third apparatus. This enables the OSNR to be measured accurately at any site in the network, using calculations in which noise shaping of the nodes can be factored in to the calculation of OSNR.

The method of pre-configuring the optical protect paths in an agile photonic network establishes a protection trail for each optical working path that may be set-up in the network. The pre-configuration is based on building an electrical layer (EXC) graph that takes into account all the connection demands in the network, and finding on this EXC graph a plurality of cycles. Next, the EXC cycles are validated at the optical layer, and are further validated against constraints. The method attempts to find an optimal cycles solution, without exhausting all possible variants.

Shortest path routing systems and methods are presented for networks with non-fully meshed vertices or nodes. The systems and methods may include a shortest path routing method in a network with non-fully meshed vertices, a network with non-fully meshed vertices, and a system for implementing the shortest path routing methods. The shortest path routing systems and methods include modifications to the Dijkstra algorithm to more accurately model a network, such as an optical or photonic network. In an exemplary embodiment, the Dijkstra algorithm is modified to represent degrees at a site with an ingress vertex (e.g., a demultiplexer) and an egress vertex (e.g., a multiplexer). In another exemplary embodiment, in addition to representing degrees as ingress and egress vertices, the Dijkstra algorithm is modified to maintain knowledge of previously visited degrees to prevent revisiting a same degree in determining a shortest path.

A multi-layer photonic network and nodes used therein are provided. The multi-layer photonic network comprises a packet network which performs switching and transfer in packet units, and a photonic network comprising optical transmission lines and photonic switches, and which accommodates the packet network. The multi-layer photonic network also has a two layer structure of optical wavelength links (O-LSPs) and packet links (E-LSPs). The O-LSPs are constituted by the optical transmission lines and comprise optical wavelength switching capability (LSC) which is capable of switching in optical wavelength units and packet switching capability (PSC) which is capable of switching in packet units at both their ends. The E-LSPs include the O-LSPs and PSCs at both their ends. Each node includes a section for automatically establishing an O-LSP according to an establishment request for an E-LSP while taking account of path information including path cost, resource consumption, and traffic quantity.

An apparatus for determining an error ratio of individual channels of a WDM optical signal comprises a wavelength-selective filter for separating the individual channels of the WDM signal and a measurement circuit for measuring an error ratio of one channel using a first decision threshold level. The measurement circuit is operable to cycle through all channels, taking an error ratio measurement for each channel in sequence with a predetermined decision threshold level. Control circuitry alters the decision threshold level for successive cycles of the measurement circuit.The apparatus measures error ratio values for each channel in turn, building up an error ratio vs. threshold pattern enabling the Q value to be obtained. Although the time taken to build up the error ratio pattern for an individual channel is not shortened, measurements are taken on each channel at much shorter intervals. This means that signal degradations can be detected much more rapidly, as these signal degradations will be reflected in each error ratio measurements, and do not require a completely updated error ratio pattern to be obtained.

An agile transparent network with a trail routing and switching (also called “engineering”) mechanism is provided that enables efficient use of regenerators and wavelengths available in the network, while maintaining a very efficient time-to-service. The trail engineering mechanism allows fast, automatic establishment of new connections based on the current network architecture, connectivity and loading and also on conditions in the connection request. Selection of regenerator sites and of the wavelengths used on each regenerator segment is performed with optimal use of current network resources, while ensuring that the quality of the selected trail is adequate for the respective call. The mechanism provides for both distance and performance balancing, and it optimizes the network response time.

A method for engineering of a connection in a WDM photonic network with a plurality of flexibility sites connected by links comprises calculating a physical end-to-end route between a source node and a destination node and setting-up a communication path along this end-to-end route. An operational parameter of the communication path is continuously tested and compared with a test threshold. The path is declared established whenever the operational parameter is above the margin tolerance. The established path is continuously monitored by comparing the operational parameter with a maintenance threshold. A regenerator is switched into the path whenever the operational parameter is under the respective threshold, or another path is assigned to the respective connection. An adaptive channel power turn-on procedure provides for increasing gradually the power level of the transmitters in the path while measuring an error quantifier at the destination receiver until a preset error quantifier value is reached. As the connection ages, the power is increased so as to maintain the error quantifier at, or under the preset value. The path operation is controlled using a plurality of optical power / gain control loops, each for monitoring and controlling a group of optical devices, according to a set of loop rules.

In an automatically switched optical network, the wavelengths are assigned to optical path based on their intrinsic physical performance and on the current network operating parameters. The wavelength performance information is organized in binning tables, based primarily on the wavelength reach capabilities. A network topology database provides the distance between the nodes of the network, which is used to determine the length of the optical path. Other network operating parameters needed for wavelength selection are also available in this database. Once a bin corresponding to the path length is identified in the binning table, the wavelength for that path is selected based on length only, or based on the length and one or more additional parameters. The optical path performance is estimated for the selected wavelength, and the search continues if the estimated path performance is not satisfactory. Several available wavelengths are searched and of those, the wavelength that is most used along the optical path in consideration or alternatively network-wide is selected and assigned. This method helps minimize wavelength fragmentation. The binning tables may have various granularities, and may be organized by reach, or by reach, wavelength spacing, the load on the respective optical path, the fiber type, etc.

Systems and methods for performing matrix operations using a path-number balanced optical network are provided. The optical network is formed as an array including active optical components and passive optical components arranged at a substantially central location of the array. The optical network includes at least NM active optical components which are used to implement a first matrix of any size N×M by embedding the first matrix in a second matrix of a larger size. The optical network performs matrix-vector and matrix-matrix operations by propagating one or more pluralities of optical signals corresponding to an input vector through the optical network.

A frequency assignment method for selecting a frequency width used on a route connecting between a start point and an end point when the start point and the end point of an optical signal are supplied in a photonic network including an optical node that includes an optical switch for switching the optical signal without electrically terminating the optical signal is disclosed. The frequency assignment method includes steps of: obtaining a correlation amount of use state of wavelength or frequency between adjacent links by referring to a route calculation result; determining a fixed frequency width or variable frequency width to be set for a communication route based on the correlation amount; and assigning the fixed frequency width or the variable frequency width on the route.