Abstract: An optical intensity control system for use with an optical switch providing individual signal paths between input and output ports. The system has optical splitters connectable to output multiplexers of the switch and has variable optical intensity controllers (VOICs) for insertion into the individual signal paths to individually control the intensity of optical signals present in the signal paths via intensity control signals. An equalizer is connected to the splitters and to the VOICs produces an estimate of the optical power of each individual switched optical signal and generates the intensity control signals. The equalizer is adapted to controllably isolate individual switched optical signals. In this way, individual and independent control of the power on each optical channel is provided.

Abstract: An optical intensity control system for use with an optical switch providing individual signal paths between input and output ports. The system has optical splitters connectable to output multiplexers of the switch and has variable optical intensity controllers (VOICs) for insertion into the individual signal paths to individually control the intensity of optical signals present in the signal paths via intensity control signals. An equalizer connected to the splitters and the VOICs produces an estimate of the optical power of each individual switched optical signal and generates the intensity control signals. The equalizer is adapted to controllably isolate individual switched optical signals. In this way, individual and independent control of the power on each optical channel is provided.

Abstract: An optical intensity control system for use with an optical switch providing individual signal paths between input and output ports. The system has a optical splitters connectable to output multiplexers of the switch and also has variable optical intensity controllers (VOICs) for insertion into the individual signal paths. The VOICs individually control the intensity of optical signals present in the signal paths in accordance with intensity control signals. An equalizer is connected to the splitters and to the VOICs, for producing an estimate of the optical power of each individual switched optical signal and generating the intensity control signals. The equalizer is adapted to controllably isolate individual switched optical signals.

Abstract: An optical intensity control system for use with an optical switch providing individual signal paths between input and output ports. The system has a optical splitters connectable to output multiplexers of the switch and also has variable optical intensity controllers (VOICs) for insertion into the individual signal paths. The VOICs individually control the intensity of optical signals present in the signal paths in accordance with intensity control signals. An equalizer is connected to the splitters and to the VOICs, for producing an estimate of the optical power of each individual switched optical signal and generating the intensity control signals. The equalizer is adapted to controllably isolate individual switched optical signals.

Abstract: An optical intensity control system for use with an optical switch providing individual signal paths between input and output ports. The system has a optical splitters connectable to output multiplexers of the switch and also has variable optical intensity controllers (VOICs) for insertion into the individual signal paths. The VOICs individually control the intensity of optical signals present in the signal paths in accordance with intensity control signals. An equalizer is connected to the splitters and to the VOICs, for producing an estimate of the optical power of each individual switched optical signal and generating the intensity control signals. The equalizer is adapted to controllably isolate individual switched optical signals.

Abstract: An optical intensity control system for use with an optical switch providing individual signal paths between input and output ports. The system has a optical splitters connectable to output multiplexers of the switch and also has variable optical intensity controllers (VOICs) for insertion into the individual signal paths. The VOICs individually control the intensity of optical signals present in the signal paths in accordance with intensity control signals. An equalizer is connected to the splitters and to the VOICs, for producing an estimate of the optical power of each individual switched optical signal and generating the intensity control signals. The equalizer is adapted to controllably isolate individual switched optical signals.

Abstract: A connection verification system that provides substantially non-intrusive connection verification for an optical switch, achieved by correlating the low-frequency contents of the input and switched signals. The results of the correlation process are compared against a connection map to determine whether the switch has operated correctly and to identify, if possible, which mis-connections have taken place. The system includes a selection unit for controllably admitting individual ones of the input signals and individual ones of the switched signals and a verification unit connected to the selection unit, for controlling operation of the selection unit as a function of a connection map and performing relative-delay-dependent signal processing operations on the signals admitted by the selection unit so as to identify connections established through the switching unit and determine their consistency with the connection map.

Abstract: A time simulation technique for determining the service availability (or unavailability) of end-to-end network connections (or paths) between source and sink nodes is disclosed. The failure could be either a single failure mode or a multiple failure mode. The time simulation apparatus includes a network representation having pluralities of nodes, links and connections; each plurality having various attributes such as relating to failure, recovery and repair mechanisms. The apparatus further includes a mechanism for selecting one instance from each of the pluralities of nodes, links and connections based on the attributes; a failure/repair module for performing a simulated failure and repair on the selected instances as appropriate; a mechanism for selecting a connection between source and sink nodes; and an arithmetic mechanism for calculating availability of the selected connection.

Abstract: An optical switch is equipped with a set of optical intensity controllers at its input, each intensity controller being driven to vary a corresponding WDM input traffic signal with a low power test signal. The switch is also equipped with optical splitters at its output and a path integrity analyzer connected to the splitters and to the intensity controllers. The path integrity analyzer generates or controls generation of the test signals applied by the intensity controllers. The path integrity analyzer also receives the tapped portions of the WDM output signals and separates them into their single-carrier components in order to recover a set of switched single-carrier optical signals. The path integrity analyzer is further provided with test signal detectors used to detect the presence of a test signal in each recovered switched single-carrier optical signal.

Abstract: A time simulation technique for determining the service availability (or unavailability) of end to and network connections (or paths) between source and sink nodes is disclosed. The method includes skips of (a) selecting a link between two network nodes; (b) performing a simulated link failure on the selected link; (c) sell sting a connection bet two network source and sink nodes; and (d) determining the unavailability and availability of the connection on under the simulated link failure condition. The method further includes (e) of repeating (c) and (a) and (b); and (f) of summoning the unavailability and availability of connections after each repetition until a predetermined number of connections have been selected, and until a simulated link failure has been performed on all links; or until the summed unavailability and availability has been determined to converge, whichever is earlier.

Abstract: A bridge and roll method for doing an in-service switch (less than 50 ms) from one set of inputs and outputs on a primary photonic switch to another set of inputs and outputs on the same or a secondary photonic switch. The bridge and roll method facilitates maintenance, repairs and upgrades on the primary photonic switch. The bridge and roll method may be reversed in order to restore the original inputs and outputs on the primary photonic switch after maintenance, repairs or upgrades have been performed. The invention also provides a method for consolidating multiple wavelengths or multiple bands into single fibers.

Abstract: A bridge and roll method for doing an in-service switch (less than 50 ms) from one set of inputs and outputs on a primary photonic switch to another set of inputs and outputs on the same or a secondary photonic switch. The bridge and roll method facilitates maintenance, repairs and upgrades on the primary photonic switch. The bridge and roll method may be reversed in order to restore the original inputs and outputs on the primary photonic switch after maintenance, repairs or upgrades have been performed. The invention also provides a method for consolidating multiple wavelengths or multiple bands into single fibers.

Abstract: A connection verification system that provides substantially non-intrusive connection verification for an optical switch, achieved by correlating the low-frequency contents of the input and switched signals. The results of the correlation process are compared against a connection map to determine whether the switch has operated correctly and to identify, if possible, which mis-connections have taken place. The system includes a selection unit for controllably admitting individual ones of the input signals and individual ones of the switched signals and a verification unit connected to the selection unit, for controlling operation of the selection unit as a function of a connection map and performing relative-delay-dependent signal processing operations on the signals admitted by the selection unit so as to identify connections established through the switching unit and determine their consistency with the connection map.

Abstract: A time simulation technique for determining the service availability (or unavailability) of end-to-end network connections (or paths) between source and sink nodes is disclosed. The failure could be either a single failure mode or a multiple failure mode. The time simulation apparatus includes a network representation having pluralities of nodes, links and connections; each plurality having various attributes such as relating to failure, recovery and repair mechanisms. The apparatus further includes a mechanism for selecting one instance from each of the pluralities of nodes, links and connections based on the attributes; a failure/repair module for performing a simulated failure and repair on the selected instances as appropriate; a mechanism for selecting a connection between source and sink nodes; and an arithmetic mechanism for calculating availability of the selected connection.

Abstract: An optical switch is equipped with a set of optical intensity controllers at its input, each intensity controller being driven to vary a corresponding WDM input traffic signal with a low power test signal. The switch is also equipped with optical splitters at its output and a path integrity analyzer connected to the splitters and to the intensity controllers. The path integrity analyzer generates or controls generation of the test signals applied by the intensity controllers. The path integrity analyzer also receives the tapped portions of the WDM output signals and separates them into their single-carrier components in order to recover a set of switched single-carrier optical signals. The path integrity analyzer is further provided with test signal detectors used to detect the presence of a test signal in each recovered switched single-carrier optical signal.

Abstract: An all optical network node, also known as a photonic node provides a gateway function for multi-vendor and multi-carrier interworking. The basis of this gateway function is the photonic node as ‘master’ performance monitor and impairment compensator. Performance monitoring in a photonic node supports network wide performance and fault management, and the triggering of network wide protection and restoration options. The photonic node also supports detection and isolation of photonic node specific faults and mis-connects, triggering protection switching to redundant modules where applicable. Advantageously, the performance monitoring drives photonic node output channel power level compensation, and potentially, dispersion compensation. This compensation facilitates a common, transparent, ‘zero-impairment’, optical gateway space capable of concatenating multi-vendor line systems, and interconnecting multi-carrier networks.

Abstract: In telecommunications involving more than one network, it is important to determine the location of a fault which may occur on a connection so that the responsible network administrator can be identified and appropriate remedial measures can be promptly performed. The invention allows sectionalization of trouble on a connection which spans more than one network administrative domain. It uses NE (near-end), FE (far-end) and Int. (intermediate) monitoring signals specific to separate layered entities associated with the connection.

Abstract: Novel techniques are disclosed for continuously monitoring parameters of delay between two nodes in a telecommunication network such as an ATM or frame relay network. The techniques use measurement cells, i.e. test cells, test frames, performance management ATM OAM cells, or performance management frame relay frames. These cells or frames contain a timestamp indicating the time a cell or frame is sent and a delay value indicating a difference between reception and transmission times of the cell or frame. Near-end and far-end as well as unidirectional or bidirectional monitoring can be performed, to support single-ended monitoring.