Abstract: This invention provides a method for commissioning and upgrading an optical ring network using its internal amplifiers as Automatic Spontaneous Emission sources of light that are used in making measurements. A modular segmented approach is adopted and the network is commissioned segment by segment. A flexible method is used for upgrading a commissioned network by adding or deleting a node or changing the internal configuration of a node. The method uses techniques for the correction of the Optical Signal to Noise Ratio induced error as well as the Spectral Filtering Error during the loss computation required for adjusting the gains of the amplifiers at each network node to an appropriate value. Since the method does not require an external laser source that needs to be moved manually from node to node it greatly reduces the commissioning time. Since it uses only the components of the network itself and does not deploy any additional device it also leads to a significant saving in cost.

Abstract: A method for powering up an optical network is provided. The method comprises remotely and safely increasing power to optical links in the optical network while monitoring signal levels in the network to discover installation errors, incorrect equipment configuration, and faulty components. In a modification to the method, attenuations of optical attenuators and gain values of optical amplifiers are set. The methods for powering up the optical network of the embodiments of the invention apply to both new optical networks and to new optical links added to pre-existing optical networks.

Abstract: This invention provides a method for commissioning an optical network using internal Automatic Spontaneous Emission (ASE) light inherently present in the optical network as a light source (the ASE light source) for measuring losses inside and between nodes in the network. A modular segmented approach is adopted and the network is commissioned segment by segment. The method uses techniques for the correction of the Optical Signal to Noise Ratio induced error as well as the Spectral Filtering Error during the loss computation required for adjusting the gains of the amplifiers at each network node to an appropriate value. Since the method does not require an external laser source that needs to be moved manually from node to node, it greatly reduces the commissioning time. Since it uses only the existing components of the network nodes it also leads to a significant saving in cost.

Abstract: A method and system for multi-level power management in an optical network is provided. They include three levels of power equalization. The first level of power management equalizes the powers of channels in a band of channels. The second level of power management equalizes the average powers of bands of channels on a fiber. The third level of control equalizes the powers of bands of channels on working and protection fibers for a path in the optical network. As a result, this multi-level power management in the network provides a dynamic, automatic method for the network to adjust to changing operating conditions and configurations and to maintain relatively stable network powers. Each level of power management may be implemented jointly or independently, and operates autonomously so that, for example, one modification comprises continuous first level control and only periodic second level control.

Abstract: A method and system for multi-level power management in an optical network is provided. They include three levels of power management. The first level of power management dynamically changes equipment settings in each module of equipment so that required module setpoint values in each module are achieved. The second level of power management determines module setpoint values for each module of equipment within each node in the optical link so that required node setpoint values are achieved. The third level of power management determines node setpoint values at each node in the optical link so that the optical link meets predetermined power specifications. If any of the three levels cannot achieve the required setpoint values, an error signal is generated by that level of power management and sent to the level of power management above it, thus initiating a higher level of power management.

Abstract: A multi-stage method and apparatus for determining a faulty component location along an optical path through an optical fiber in an optical network are disclosed. A total power of the optical fiber, and a total wavelength power as a sum of powers of the individual wavelengths at a plurality of local detection points are measured and compared at the local detection points, followed by determining whether or not a faulty detection point exists along the optical path. If a fault is identified, the method provides a multi-stage fault detection procedure, including measuring a total wavelength power loss between a local detection point and an adjacent detection point, between the local detection point and multiple non-adjacent detection points, and a correlation of the measured total wavelength power losses between the various detection points. A corresponding apparatus for determining the faulty component location in the optical network is also provided.

Abstract: A method for automatic initialization of an optical network is provided. A network management system (NMS) performs remote determination of span losses and sets the operating points of network components. The initialization method comprises remotely and automatically setting target gains of optical amplifiers and signal power levels at transmitters and receivers to required operating values. The methods for initialization of the optical network of the embodiments include gain excursion minimization (GEM) for individual channels passing through amplifiers and/or pre-emphasis of the optical link, where channel powers at the transmitters are biased to compensate for the effects of optical amplifiers gain ripple.

Abstract: A method for determining locations and gain settings of optical amplifiers in an optical network is provided. The method comprises evaluating allowable amplifier locations and successively eliminating selected locations until no further locations can be eliminated without the network violating predetermined specifications. This systematic method is applicable to a variety of network topologies and takes into account existing network limitations. In one embodiment, the method for determining the locations and gain settings of the amplifiers uses the amount of operating margin in the network to select locations to be eliminated. In another embodiment, the method is repeated a number of times with different selections of amplifier locations, and the method providing the arrangement with the least number of amplifiers is chosen.

Abstract: A method for determining locations and gain settings of amplifiers in an optical network is provided. The method comprises evaluating allowable amplifier locations, randomly generating sets of amplifier locations from the allowable amplifier locations, and applying genetic operations to the sets of amplifier locations until a predetermined exit condition is satisfied. This systematic method is applicable to a variety of network topologies and takes into account existing network limitations. In one embodiment, the method for determining the locations and gain settings of the amplifiers uses the amount of operating margin in the network to select sets of locations to be eliminated. In another embodiment, the method takes into account and determines the placement of dispersion compensation modules (DCMs), choices of which are provided by DCM placement procedures.

Abstract: An apparatus and method for minimizing channel gain excursion in an optical system with automatic gain control is provided. The apparatus includes a feedback control loop which dynamically regulates the target gain of an automatic gain controlled (AGC) amplifier so as to compensate for the action of the AGC amplifier to maintain a constant linear average gain without accounting for the distribution of channels that carry signals across the amplifier spectral gain profile, which causes gain excursion of individual channels. The feedback control loop measures gain of individual channels and uses these measurements to regulate the target gain of the amplifier so as to minimize gain excursion of individual channels. If required, the apparatus may be integrated into a package. In one embodiment, the method for regulating the target gain is to maintain constant gain for all channels irrespective of the number of channels that carry a signal. This method is simple and guarantees no gain excursion.

Abstract: A method and system for multi-level power management in an optical network is provided. They include three levels of power management. The first level of power management dynamically changes equipment settings in each module of equipment so that required module setpoint values in each module are achieved. The second level of power management determines module setpoint values for each module of equipment within each node in the optical link so that required node setpoint values are achieved. The third level of power management determines node setpoint values at each node in the optical link so that the optical link meets predetermined power specifications. If any of the three levels cannot achieve the required setpoint values, an error signal is generated by that level of power management and sent to the level of power management above it, thus initiating a higher level of power management.

Abstract: A method and system for determining location and value of dispersion compensating modules (DCMs) in an optical network is provided. The method comprises evaluating possible DCM values and locations and successively adding selected combinations to the network until the dispersion limits of the network are met. This systematic method is applicable to a variety of network topologies. In one embodiment, the method for determining the location and value of the DCMs uses the amount of compensated effective dispersion over all lightpaths that pass through the DCM to select the combinations. In another embodiment, the method is repeated a number of times with different selections of DCM value and location combinations, and the method providing the least number of DCMs and the lowest DCM values is chosen.

Abstract: A method for determining optimal locations and values of dispersion compensating modules (DCMs) in an optical network is provided. The method comprises repeatedly evaluating possible combinations of DCM values and locations and adding to the combination having the lowest score until a solution of DCMs is formed that satisfies the dispersion limits of the network. This method provides an optimal solution with, for example, the lowest value of DCMs necessary to meet dispersion specifications. In one embodiment, the method for determining the optimal location and value of the DCMs uses a priority queue to store the different combinations of DCM values and locations. Modifications to the method include variations in the score function, for example to minimize the total cost of the DCMs. In another embodiment, a series of priority queues are used to improve the efficiency of the method by reducing the amount of processing required to sort the priority queues.

Abstract: A method and system for determining location and value of dispersion compensating modules (DCMS) in an optical network is provided. The method comprises evaluating possible DCM values and locations and successively adding selected combinations to the network until the dispersion limits of the network are met. This systematic method is applicable to a variety of network topologies. In one embodiment, the method for determining the location and value of the DCMs uses the amount of compensated effective dispersion over all lightpaths that pass through the DCM to select the combinations. In another embodiment, the method is repeated a number of times with different selections of DCM value and location combinations, and the method providing the least number of DCMs and the lowest DCM values is chosen.

Abstract: The present invention provides an all-optical dynamic gain equalizer of an open-loop design using nonlinear optical materials for equalizing channel power without the need of complex electronics and close-loop control, and provides pulse reshaping and in some embodiments noise reduction at no extra cost. The invention achieves restoration of spectral power uniformity by employing nonlinear optical limiters with desirable power transfer function curves to each of the optical signals to be equalized. The invention provides the highly desirable functions of dynamic gain equalization, and optical pulse reshaping. Some embodiments constructed according to the invention provide signal dynamic range control by biasing the nonlinear optical limiter with a biasing optical signal.

Abstract: A method for determining optimal locations and values of dispersion compensating modules (DCMs) in an optical network is provided. The method comprises repeatedly evaluating possible combinations of DCM values and locations and adding to the combination having the lowest score until a solution of DCMs is formed that satisfies the dispersion limits of the network. This method provides an optimal solution with, for example, the lowest value of DCMs necessary to meet dispersion specifications. In one embodiment, the method for determining the optimal location and value of the DCMs uses a priority queue to store the different combinations of DCM values and locations. Modifications to the method include variations in the score function, for example to minimize the total cost of the DCMs. In another embodiment, a series of priority queues are used to improve the efficiency of the method by reducing the amount of processing required to sort the priority queues.

Abstract: A method and system for multi-level power management in an optical network is provided. They include three levels of power equalization. The first level of power management equalizes the powers of channels in a band of channels. The second level of power management equalizes the average powers of bands of channels on a fiber. The third level of control equalizes the powers of bands of channels on working and protection fibers for a path in the optical network. As a result, this multi-level power management in the network provides a dynamic, automatic method for the network to adjust to changing operating conditions and configurations and to maintain relatively stable network powers. Each level of power management may be implemented jointly or independently, and operates autonomously so that, for example, one modification comprises continuous first level control and only periodic second level control.

Abstract: A method for automatic initialization of an optical network is provided. A network management system (NMS) performs remote determination of span losses and sets the operating points of network components. The initialization method comprises remotely and automatically setting target gains of optical amplifiers and signal power levels at transmitters and receivers to required operating values. The methods for initialization of the optical network of the embodiments include gain excursion minimization (GEM) for individual channels passing through amplifiers and/or pre-emphasis of the optical link, where channel powers at the transmitters are biased to compensate for the effects of optical amplifiers gain ripple.

Abstract: A method for powering up an optical network is provided. The method comprises remotely and safely increasing power to optical links in the optical network while monitoring signal levels in the network to discover installation errors, incorrect equipment configuration, and faulty components. In a modification to the method, attenuations of optical attenuators and gain values of optical amplifiers are set. The methods for powering up the optical network of the embodiments of the invention apply to both new optical networks and to new optical links added to pre-existing optical networks.

Abstract: A method for determining locations and gain settings of amplifiers in an optical network is provided. The method comprises evaluating allowable amplifier locations, randomly generating sets of amplifier locations from the allowable amplifier locations, and applying genetic operations to the sets of amplifier locations until a predetermined exit condition is satisfied. This systematic method is applicable to a variety of network topologies and takes into account existing network limitations. In one embodiment, the method for determining the locations and gain settings of the amplifiers uses the amount of operating margin in the network to select sets of locations to be eliminated. In another embodiment, the method takes into account and determines the placement of dispersion compensation modules (DCMs), choices of which are provided by DCM placement procedures.