Abstract: An optical transport network (OTN) node including a plurality of optical circuit switches (OCSs), each OCS being a respective degree of the OTN node, at least two of the OCSs including an input port configured to be connected to a respective optical transport fiber outside of the OTN node, at least one first output port connected to a first switching layer, and at least one second output port connected to a second switching layer. The first and second switching layers have different levels of granularity, such as but not limited to a wavelength switched layer, a band switched layer or a fiber switched layer.

Abstract: Margin hedging in optical communication systems allows for overhead within the optical system. A machine learning model can be trained using the output of a physics based simulation of the optical system as well as the features of the optical system. A trained machine learning model can adjust the results of a physics based simulation of an optical network to more accurately match the adjusted simulation results to the “true” performance of the optical network. The margins of the optical communication system can be more tailored to the true performance of a designed or planned optical system.

Abstract: In an asynchronous optical modulation system, a drive circuit may generate a plurality of dither tones in accordance with a predetermined dither frequency ratio. Based on the components of the dither frequency ratio, the optical modulation system may be configured to determine a feedback signal magnitude component that is independent of the delay ? and a feedback signal sign component that is also independent of the delay ?. A feedback signal that is independent of the delay ? can then be reconstructed based on the feedback signal magnitude component and the feedback signal sign component.

Abstract: A system and method are disclosed to characterize and correct for the effects of IQ skew and insertion loss in a coherent optical transmitter. The coherent optical transmitter receives a digital data signal including in-phase (I) and quadrature (Q) components and generates corresponding first and second dither signals. The first dither signal may be combined with the I component and the second dither signal may be combined with the Q component to generate I and Q combined signals, which may be converted into I and Q analog waveforms. An optical signal may be generated corresponding to the I and Q analog waveforms for transmission over an optical fiber. The IQ skew and/or insertion loss for the coherent optical transmitter may then be calculated based on the optical signal using the disclosed dither tone processing techniques in order to correct IQ skew and/or insertion loss impairment.

Abstract: A system and method are disclosed to characterize and correct for the effects of IQ skew and insertion loss in a coherent optical transmitter. The coherent optical transmitter receives a digital data signal including in-phase (I) and quadrature (Q) components and generates corresponding first and second dither signals. The first dither signal may be combined with the I component and the second dither signal may be combined with the Q component to generate I and Q combined signals, which may be converted into I and Q analog waveforms. An optical signal may be generated corresponding to the I and Q analog waveforms for transmission over an optical fiber. The IQ skew and/or insertion loss for the coherent optical transmitter may then be calculated based on the optical signal using the disclosed dither tone processing techniques in order to correct IQ skew and/or insertion loss impairment.

Abstract: A method and an apparatus for non-blocking Mach-Zehnder Modulator (MZM) arm imbalance monitoring and control through tones are disclosed herein. An optical transmitter may include an MZM to supply a first portion of light to an in-phase arm and a second portion to a quadrature arm of the MZM. The optical transmitter may apply modulator arm adjustments and dither signals to the two portions. Then, the MZM may combine the two portions into an optical output signal. The optical transmitter may tap the optical output signal to provide a first portion of the optical output signal and transmit a second portion. Also, the optical transmitter may obtain first error signals, based on the first dither signal, and second error signals, based on the second dither signal, of the first portion of the output signal. The optical transmitter may change the modulator arm adjustments based on the error signals.

Abstract: A method and an apparatus for non-blocking Mach-Zehnder Modulator (MZM) arm imbalance monitoring and control through tones are disclosed herein. An optical transmitter may include an MZM to supply a first portion of light to an in-phase arm and a second portion to a quadrature arm of the MZM. The optical transmitter may apply modulator arm adjustments and dither signals to the two portions. Then, the MZM may combine the two portions into an optical output signal. The optical transmitter may tap the optical output signal to provide a first portion of the optical output signal and transmit a second portion. Also, the optical transmitter may obtain first error signals, based on the first dither signal, and second error signals, based on the second dither signal, of the first portion of the output signal. The optical transmitter may change the modulator arm adjustments based on the error signals.

Abstract: In an asynchronous optical modulation system, a drive circuit may generate a plurality of dither tones in accordance with a predetermined dither frequency ratio. Based on the components of the dither frequency ratio, the optical modulation system may be configured to determine a feedback signal magnitude component that is independent of the delay ? and a feedback signal sign component that is also independent of the delay ?. A feedback signal that is independent of the delay ? can then be reconstructed based on the feedback signal magnitude component and the feedback signal sign component.

Abstract: A digital signal processor (DSP) of an optical receiver may receive information representing a polarization multiplexed signal including tone information. The polarization multiplexed signal may have an uncorrected state of polarization (SOP). The DSP may determine sets of Stokes parameters based on the tone information. The DSP may determine a set of polarization parameters based on the sets of Stokes parameters. The DSP may apply, based on the set of polarization parameters, a set of operations to the information representing the polarization multiplexed signal. An operation, of the set of operations, may represent a rotation or a phase retardation of the polarization multiplexed signal and may correspond to a polarization parameter of the set of polarization parameters. The set of operations may be applied to the information representing the polarization multiplexed signal in order to generate information representing the polarization multiplexed signal with a corrected SOP.

Abstract: An apparatus is provided. The apparatus may include a drive circuit that selectively supplies a first plurality of electrical signals and a second plurality of electrical signals to a modulation circuit. Based on the first plurality of electrical signals, the modulation circuit may output a first in-phase component being modulated in accordance with a first tone having a first frequency and a first quadrature component being modulated in accordance with a second tone having a second frequency different than the first frequency. Based on the second plurality of electrical signals, the modulation circuit may output a second optical signal having a second in-phase component being modulated in accordance with the second tone and a second quadrature component being modulated in accordance with the first tone.

Abstract: A digital signal processor (DSP) of an optical receiver may receive information representing a polarization multiplexed signal including tone information. The polarization multiplexed signal may have an uncorrected state of polarization (SOP). The DSP may determine sets of Stokes parameters based on the tone information. The DSP may determine a set of polarization parameters based on the sets of Stokes parameters. The DSP may apply, based on the set of polarization parameters, a set of operations to the information representing the polarization multiplexed signal. An operation, of the set of operations, may represent a rotation or a phase retardation of the polarization multiplexed signal and may correspond to a polarization parameter of the set of polarization parameters. The set of operations may be applied to the information representing the polarization multiplexed signal in order to generate information representing the polarization multiplexed signal with a corrected SOP.