Abstract: Methods and systems enable optimized placement of wavelength shifters in optical networks. The wavelength shifters may include O-E-O regenerators for a single wavelength and all optical wavelength shifters for one or more wavelengths. An auxiliary graph is used to represent various links in a provisioned optical path. By applying cost values to each of the links, different types of optimizations for network resource utilization may be realized.

Abstract: Methods and systems for periodic optical filtering to identify tone modulated optical signals may enable relatively rapid scanning of an optical signal to identify individual optical channels. The optical signal having tone modulated optical channels may be scanned over a free spectral range of a periodic optical filter, such as a comb filter, to generate a filtered signal. Then, center optical frequencies for each of the optical channels in the filtered signal may be determined by demodulation and digital signal processing.

Abstract: A method of mapping virtual optical networks (VONs) to a physical network that includes physical links that connect physical nodes. The method includes reading physical network information, VON demands, and technology constraints of the physical network. The method includes determining whether an iteration parameter violates an iterative condition that determines whether to continue processing the VON demands. If not, the method includes determining whether there are unprocessed subgroups of the VON demands. In response to there being unprocessed subgroups, the method includes selecting a subgroup of the VONs. The method includes computing feasible mapping patterns for the subgroup of the VONs. The method includes finding a size of a largest subset of the subgroup that has a feasible mapping and slot assignment solution. The method includes finding a mapping solution of the subset that has a feasible slot assignment and a slot assignment of the mapping solution.

Abstract: A method employing resource orchestration algorithms may find a fewest number of working data centers (DCs) to guarantee K-connect survivability using an overlay network representing a physical optical network. The overlay network may not include certain topological features of the physical optical network. A risk-based algorithm may result in fewer working DCs for K-connect survivability. A delay-based algorithm may be more suitable for delay-sensitive cloud applications.

Abstract: A method of mapping virtual optical networks (VONs) to a physical network that includes physical links that connect physical nodes. The method includes reading physical network information, VON demands, and technology constraints of the physical network. The method includes determining whether an iteration parameter violates an iterative condition that determines whether to continue processing the VON demands. If not, the method includes determining whether there are unprocessed subgroups of the VON demands. In response to there being unprocessed subgroups, the method includes selecting a subgroup of the VONs. The method includes computing feasible mapping patterns for the subgroup of the VONs. The method includes finding a size of a largest subset of the subgroup that has a feasible mapping and slot assignment solution. The method includes finding a mapping solution of the subset that has a feasible slot assignment and a slot assignment of the mapping solution.

Abstract: Methods and systems for periodic optical filtering to identify tone modulated optical signals may enable relatively rapid scanning of an optical signal to identify individual optical channels. The optical signal having tone modulated optical channels may be scanned over a free spectral range of a periodic optical filter, such as a comb filter, to generate a filtered signal. Then, center optical frequencies for each of the optical channels in the filtered signal may be determined by demodulation and digital signal processing.

Abstract: Virtual optical network (VON) provisioning using implicit encoding of mapping constraints may include evaluating mapping choices to exclude certain mapping patterns before evaluating the mapping patterns. For each virtual node in a VON request, candidate physical nodes may be assigned and evaluated for compliance with constraints associated with the VON request. The constraints may be expanded to allow for various selection criteria for the VON request. Multiple VON requests may be simultaneously evaluated to find optimal solutions for the physical network.

Abstract: A method employing resource orchestration algorithms may find a fewest number of working data centers (DCs) to guarantee K-connect survivability and a fewest number of virtual machines (VMs) among the DCs using an overlay network representing a physical optical network. The overlay network may exclude certain topological features of the physical optical network. An intra-request VM sharing method may share VMs among DCs allocated for an aggregation request. An intra-request VM sharing method may share VMs among DCs represented in the overlay network and among multiple aggregation requests.

Abstract: Methods and systems for using modulation frequencies for optical channel monitoring with periodic optical filtering may allocate modulation frequencies based on bandwidth slices of an optical spectrum. The bandwidth slices may have an equal spectral band that is associated with a respectively unique modulation frequency. An optical carrier aligning with a bandwidth slice may be modulated using the modulation frequency assigned to that bandwidth slice. Additionally, the bandwidth slices may be used to determine a maximum frequency error of an optical carrier when received, such as from frequency drift during transmission.

Abstract: Methods and systems may estimate nonlinear penalties for optical paths using spectral inversion in optical transport networks. Certain values of nonlinear transfer functions for nonlinear penalty estimation may be pre-calculated for optical paths between given nodes. When an optical path computation for using spectral inversion between a given source node and a given destination node is desired, the pre-calculated values may be concatenated for improved computational efficiency.

Abstract: Flexible VON provisioning may include calculating a candidate mapping pattern to satisfy a virtual optical network (VON) demand based on virtual-to-physical node mapping choices. A distance-adaptive routing and spectral slot assignment evaluation of the candidate mapping pattern may be performed. When the VON demand is satisfied by the candidate mapping pattern, the candidate mapping pattern may be added to a valid mapping patterns list. A final mapping pattern may be selected from the valid mapping patterns list, the final mapping pattern having one of a lowest slot layer and a smallest overall slot usage on the valid mapping patterns list. Then, network resources may be reserved based on the final mapping pattern selected to service the VON demand.

Abstract: A method of provisioning a network may include receiving a mapping solution for one or more virtual optical network (VON) requests including virtual nodes and virtual links. The mapping solution may include one mapping pattern for each VON request and each mapping pattern may include an ordered list of physical nodes. The method may also include formulating inequality constraint equations based on physical links that are shared by multiple virtual links. The method may also include formulating range constraint equations for each virtual link based on a physical link for each virtual link with a lowest number of optical transmission slots such that each virtual link occupy a same optical transmission slot across all physical links that are traversed by the virtual link. The inequality and range constraint equations may be solved with satisfiability modulo theories to obtain a slot assignment solution.

Abstract: A method of provisioning an optical network may include receiving one or more virtual optical network (VON) requests. Each VON request may include one or more virtual nodes and one or more virtual links. The virtual nodes may have one or more candidate nodes corresponding to a physical optical network. The method may also include identifying mapping patterns for VON requests by iteratively assigning each virtual node to one of their candidate nodes for each combination of candidate nodes and assigning each virtual link to corresponding physical links. The method may also include formulating a first set of constraint equations based on mapping patterns for the VON requests and formulating a second set of constraint equations based on physical optical network constraints. The first and second set of constraint equations may be solved by satisfiability modulo theories to obtain a mapping solution.

Abstract: A method for network analysis includes determining an initial set of demands upon the resources of a network, determining a new set of demands upon the resources of the network, apply a policy for assigning a demand of the new set of demands to a demand of the initial set of demands, create a dependency for the assignment of the demand of the new set of demands to the demand of the initial set of demands, construct a sub-graph including the dependency, and incorporate the sub-graph into a resource-oriented-dependency graph. Each demand includes a quantification.

Abstract: Methods and systems are provided for flexible placement of spectral inverters in an optical network. The method includes identifying a first transmission path coupling a transmitter and a receiver. The first transmission path includes a first node for assignment of a first spectral inverter. The method further includes estimating a first optical signal-to-noise ratio (OSNR) penalty of nonlinear phase noise (NLPN) on the first transmission path with the first spectral inverter assigned to the first node, and based on the first estimated OSNR penalty of NLPN being less than an NLPN penalty threshold, assigning the first spectral inverter to the first node.

Abstract: A system includes an optical power meter operable to generate an optical power signal corresponding to the optical power of a received output signal generated by an optical IQ-modulator. The system further includes a processor operable to receive the optical power signal and determine, based on a minimization algorithm and the received optical power signal, a first bias voltage to be applied to a first sub-modulator of the optical IQ-modulator and a second bias voltage to be applied to a second sub-modulator of the optical IQ-modulator. The system may also include a peak power meter operable to generate a peak power signal corresponding to the peak power of the received output signal generated by the optical IQ-modulator, wherein the processor is further operable to determine, based on a minimization algorithm and the received peak power signal, a third bias voltage to be applied to a phase shift component of the optical IQ-modulator.

Abstract: Methods and systems are provided for optical signal transmission using span-wise spectrum management. The method includes transmitting a first optical signal at a first wavelength by a control system. The first optical signal has a first optical path distance. The method further includes determining a first guard band requirement for the first optical signal, and transmitting a second optical signal by the control system. The second optical signal has a second optical path distance. The method includes determining a second guard band requirement for the second optical signal, and placing the second optical signal spectrally adjacent to the first optical signal by selecting a second wavelength. The second wavelength is selected to satisfy the first and second guard band requirements.

Abstract: Virtual optical network (VON) provisioning using implicit encoding of mapping constraints may include evaluating mapping choices to exclude certain mapping patterns before evaluating the mapping patterns. For each virtual node in a VON request, candidate physical nodes may be assigned and evaluated for compliance with constraints associated with the VON request. The constraints may be expanded to allow for various selection criteria for the VON request. Multiple VON requests may be simultaneously evaluated to find optimal solutions for the physical network.

Abstract: A method employing resource orchestration algorithms may find a fewest number of working data centers (DCs) to guarantee K-connect survivability and a fewest number of virtual machines (VMs) among the DCs using an overlay network representing a physical optical network. The overlay network may exclude certain topological features of the physical optical network. An intra-request VM sharing method may share VMs among DCs allocated for an aggregation request. An intra-request VM sharing method may share VMs among DCs represented in the overlay network and among multiple aggregation requests.

Abstract: A method for routing and wavelength assignment for optical network resources required for a plurality of virtual network requests includes receiving the plurality of virtual network requests. The method further includes determining a number of virtual links for each virtual network request. The method includes sorting the plurality of virtual network requests based on the number of virtual links, and selecting a virtual network request from the plurality of virtual network requests and setting a number of allowable spans. Additionally, the method includes determining whether a valid virtual node mapping exists for the virtual network request on any of a plurality of wavelengths based on the allowable spans, and based on determining that no valid virtual node mapping exists on any of the plurality of wavelengths, incrementing the number of allowable spans.