At&t Intellectual Property I, L.p.

At+t Corp.

Mikhail Brodsky

Peter David Magill

Mikhail Boroditsky

Mark David Feuer

Nicholas J Frigo

Cristian Antonelli

Jungmi Oh

Lynn Nelson

Antonio Mecozzi

Paul Shala Henry

A system and method for securing communications between a plurality of users communicating over an optical network. The system utilizes a fixed or tunable source optical generator to generate entangled photon pairs, distribute the photons and establish a key exchange between users. The distribution of entangled photon pairs is implemented via at least one wavelength selective switch.

Architecture for reconfigurable quantum key distribution networks based on entangled photons directed by a wavelength selective switch

A system and method for securing communications over a wave division multiplexing optical network between a plurality of users connected to the network. The system utilizes a primary optical source generator that is either tunable, or capable of generating a plurality of wavebands of different frequencies equal to the sum of wavebands serving individual users of the network to facilitate a key exchange between the individual users of the network using summed wavebands, each of which serving an individual user.

Architecture for reconfigurable quantum key distribution networks based on entangled photons by wavelength division multiplexing

A quantum key distribution system is deployed in an optical fiber network transporting classical data traffic. A source of entangled photon pairs is used to generate quantum keys. Classical data traffic is typically transported over channels in the C-band. If a pair of channels for transport of quantum data is available within the C-band, then the source of entangled photon pairs is tuned to emit in a pair of channels in the C-band. If a pair of channels for transport of quantum data is not available within the C-band, then the source of entangled photon pairs is tuned to emit in a pair of channels in a combined S-band and L-band. When a periodically-poled lithium niobate waveguide pumped with a laser is used for the source of entangled photon pairs, the output spectral properties are tuned by varying the temperature of the waveguide.

Bandwidth provisioning for the entangled photon system by adjusting the phase matching conditions

A method and memory medium in a wavelength division multiplexing (WDM) network that communicates multiplexed signals representing a plurality of communication channels to determine received signal quality are disclosed. Generally, the signals format the plurality of communication channels to impart a distinctive noise profile in time or frequency for each channel; and collectively process the channels at a digital signal processing device to measure the signal-to-noise ratio.

Method for measuring signal quality in WDM optical networks

Described is a method and system for reducing system penalty from polarization mode dispersion. The method includes receiving a plurality of signals at a receiving end of a transmission line, each signal being received on one of a plurality of channels of the transmission line and measuring a signal degradation of at least one of the channels of the transmission line. An amount of adjustment of a polarization controller is determined based on the signal degradation, the amount of adjustment being selected to reduce the polarization mode dispersion. The amount of adjustment is then transmitted to the polarization controller.

Method and apparatus for broadband mitigation of polarization mode dispersion

Systems and methods are described that measure the OSNR of an optical channel. Embodiments provide OSNR measurement methods that distinguish the intensities of the coherent modulated signal from the incoherent noise intensity occupying the same optical band using a calibration factor &#x3b6;.

Calibration factor for interferometric optical signal-to-noise ratio measurement

Interferometric optical signal-to-noise ratio measurement using a calibration factor

Systems and methods are described that derive a relationship between an optical transmitter's extinction ratio (E) and its interferogram wing-to-peak ratio (I). The change in an optical transmitter's Icorrelates with a change in measured E. As the Eof a telecom signal changes, the power of the modulated signal's interferogram wings change. After a relationship between Iand measured Ehas been derived for an optical transmitter, the relationship may be used after deployment to determine an Eby measuring an I.

System and method for measuring the extinction ratio of an optical transmitter using an interferogram wing-to-peak ratio

Differences in the interferometric patterns of modulated telecommunication signals and broadband optical noise sources are identified and are exploited in measuring the optical signal-to-noise measurements in reconfigurable photonic networks. A light output power from said interferometer corresponding to a specified delay setting in the interferometer is measured, and a coherent optical signal is distinguished from the incoherent optical noise based on the light output power measurement.

Interferometric method and apparatus for measuring optical signal quality in optical communications system

Disclosed is a method and apparatus for determining the birefringence autocorrelation length of a fiber in a non-destructive manner. The PMD of an optical fiber is measured over a first optical spectrum. A Faraday rotation angle is measured over a second optical spectrum. The birefringence autocorrelation length is determined from the measuring of the PMD and the Faraday rotation angle.

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Millburn, NJ, United States of America

Mikhail Brodsky