Patents by Inventor Fabrizio Forghieri
Fabrizio Forghieri has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 9584260Abstract: A method for transmitting a coherent optical data signal includes receiving a data signal from an interface, and encoding the data signal with a forward error correcting (FEC) encoder according to a mix of modulation formats. The FEC encoder generates an FEC encoded signal which is used to generate modulation symbols according to the modulation formats. The FEC encoded signal of modulation symbols is spectrally shaped to generate a shaped signal, and pre-distorted before transmission. The shaped signal is pre-distorted by adding a predetermined amount of chromatic dispersion to generate a smoothed signal, and the smoothed signal is transmitted according to the modulation formats.Type: GrantFiled: March 6, 2014Date of Patent: February 28, 2017Assignee: Cisco Technology, Inc.Inventors: Chris Fludger, Theodor Kupfer, Fabrizio Forghieri, Pierluigi Poggiolini, Gabriella Bosco, Andrea Carena, Vittorio Curri
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Patent number: 9515745Abstract: A coherent optical receiver including an optical transducer, an adaptive filter, and a processor updates the adaptive filter according to a metric derived in Stokes space. The optical transducer receives an optical signal corresponding to a modulated signal of symbols. The optical transducer also determines a first signal corresponding to a first polarization of the optical signal and a second signal corresponding to a second polarization of the optical signal. The adaptive filter recovers a first equalized signal and a second equalized signal from the first signal and the second signal. The first equalized signal and the second equalized signal form an equalized modulated signal of symbols. The processor calculates a set of Stokes parameters from the equalized modulated signal and updates the adaptive filter based on a metric derived from the set of Stokes parameters.Type: GrantFiled: March 6, 2014Date of Patent: December 6, 2016Assignee: Cisco Technology, Inc.Inventors: Gabriella Bosco, Monica Visintin, Pierluigi Poggiolini, Fabrizio Forghieri, Andrea Carena, Vittorio Curri
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Publication number: 20160142179Abstract: A method for transmitting a coherent optical data signal includes receiving a data signal from an interface, and encoding the data signal with a forward error correcting (FEC) encoder according to a mix of modulation formats. The FEC encoder generates an FEC encoded signal which is used to generate modulation symbols according to the modulation formats. The FEC encoded signal of modulation symbols is spectrally shaped to generate a shaped signal, and pre-distorted before transmission. The shaped signal is pre-distorted by adding a predetermined amount of chromatic dispersion to generate a smoothed signal, and the smoothed signal is transmitted according to the modulation formats.Type: ApplicationFiled: March 6, 2014Publication date: May 19, 2016Applicant: Cisco Technology, Inc.Inventors: Chris Fludger, Theodor Kupfer, Fabrizio Forghieri, Pierluigi Poggiolini, Gabriella Bosco, Andrea Carena, Vittorio Curri
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Publication number: 20150256268Abstract: A coherent optical receiver including an optical transducer, an adaptive filter, and a processor updates the adaptive filter according to a metric derived in Stokes space. The optical transducer receives an optical signal corresponding to a modulated signal of symbols. The optical transducer also determines a first signal corresponding to a first polarization of the optical signal and a second signal corresponding to a second polarization of the optical signal. The adaptive filter recovers a first equalized signal and a second equalized signal from the first signal and the second signal. The first equalized signal and the second equalized signal form an equalized modulated signal of symbols. The processor calculates a set of Stokes parameters from the equalized modulated signal and updates the adaptive filter based on a metric derived from the set of Stokes parameters.Type: ApplicationFiled: March 6, 2014Publication date: September 10, 2015Applicant: Cisco Technology, Inc.Inventors: Gabriella Bosco, Monica Visintin, Pierluigi Poggiolini, Fabrizio Forghieri, Andrea Carena, Vittorio Curri
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Patent number: 8682175Abstract: For an optical network link, a receiving node monitors optical performance and upon determination of lowered optical performance for an extended period of time, the node can signal a transmitting node to lower bit transfer rate from a nominal bit transfer rate. The receiving node has a transponder which has a digital electronic variable bandwidth filter to process the digitized signals at the lowered bit transfer rate to increase the SNR of the signals. Optical performance of the link is optimized although at the lowered bit transfer rate.Type: GrantFiled: August 28, 2008Date of Patent: March 25, 2014Assignee: Cisco Technology, Inc.Inventors: Fabrizio Forghieri, Luca Della Chiesa
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Patent number: 8311417Abstract: Various example embodiments are disclosed. According to one example embodiment, a phase error is estimated in a series of digital symbols of a phase-modulated signal, where the signal is subject to a non-linear phase shift error due to transmission of the signal through an optical fiber. A phase correction of an instant digital symbol that succeeds the series of digital symbols is estimated, where the estimated phase correction is based on the estimated phase errors in the series of digital symbols. The estimated phase correction of the instant digital symbol is limited to a maximum absolute value, and the estimated phase correction is applied to the instant digital symbol of the signal.Type: GrantFiled: March 10, 2009Date of Patent: November 13, 2012Assignee: Cisco Technology, Inc.Inventors: Pierluigi Poggiolini, Andrea Carena, Vittorio Curri, Fabrizio Forghieri
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Patent number: 8275257Abstract: Methods and apparatus for varying the transmission rate of a signal transmitted within a dense wavelength division multiplexing (DWDM) system or network are disclosed. According to one aspect of the present invention, a method includes obtaining a first signal and determining a transmission rate associated with the first. If it is determined that the transmission rate is a first rate, the method includes processing the first signal as having a first transmission format and the first rate. Alternatively, it is determined that the transmission rate is not the first rate and is a second rate, the method includes processing the first signal as having a second transmission format and a second rate.Type: GrantFiled: April 17, 2007Date of Patent: September 25, 2012Assignee: Cisco Technology, Inc.Inventors: Fabrizio Forghieri, Luca Della Chiesa
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Patent number: 8218969Abstract: OFDM (Orthogonal Frequency Division Multiplexing) has been proposed for processing signals over WDM channels in an optical network. The number of OFDM sub-carrier channels utilized in transmitting optical signals from a transmitting node to a remote is adapted to the quality of transmission in a WDM channel. Responsive to control signals from the remote node, the number of used sub-carrier channels is set to optimize optical performance of the WDM channel.Type: GrantFiled: March 18, 2009Date of Patent: July 10, 2012Assignee: Cisco Technology, Inc.Inventors: Fabrizio Forghieri, Marco Croci, Luca Della Chiesa
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Measurement of optical fiber length and determination of chromatic dispersion over the optical fiber
Patent number: 7808623Abstract: In one embodiment, first optical signal can be generated at a first end of an optical fiber segment at a first time. The first optical signal can be detected at a second end of the optical fiber segment at a second time. A second optical signal can be generated at a second end of the optical fiber segment at a third time in response to the detection of the first optical signal. The second optical signal can be detected at the first end of the optical fiber segment at a fourth time. A length of the optical fiber segment can be determined based on a difference between the second time and the first time, a difference between the third time and the second time, and a difference between the fourth time and the third time.Type: GrantFiled: October 15, 2007Date of Patent: October 5, 2010Assignee: Cisco Technology, Inc.Inventors: Stefano Piciaccia, Fabrizio Forghieri, Ornan Gerstel, Gabriele Maria Galimberti -
Patent number: 7809271Abstract: An economic way of determining the chromatic dispersion along a link of a DWDM network is provided. A transmitter modulates the output signals of two lasers operating at two different wavelengths and the modulated output signals are sent into the link. Detectors at each one of a plurality of detection sites along the link determine a phase difference in modulation between the output signals of the two lasers. The chromatic dispersion for each detection site can be calculated from the modulation frequency and determined phase differences at that site.Type: GrantFiled: May 23, 2007Date of Patent: October 5, 2010Assignee: Cisco Technology Inc.Inventors: Stefano Piciaccia, Fabrizio Forghieri
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Publication number: 20100239259Abstract: OFDM (Orthogonal Frequency Division Multiplexing) has been proposed for processing signals over WDM channels in an optical network. The number of OFDM sub-carrier channels utilized in transmitting optical signals from a transmitting node to a remote is adapted to the quality of transmission in a WDM channel. Responsive to control signals from the remote node, the number of used sub-carrier channels is set to optimize optical performance of the WDM channel.Type: ApplicationFiled: March 18, 2009Publication date: September 23, 2010Applicant: CISCO TECHNOLOGY, INC.Inventors: Fabrizio Forghieri, Marco Croci, Luca Della Chiesa
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Measurement of Optical Fiber Length and Determination of Chromatic Dispersion Over the Optical Fiber
Publication number: 20090097014Abstract: In one embodiment, first optical signal can be generated at a first end of an optical fiber segment at a first time. The first optical signal can be detected at a second end of the optical fiber segment at a second time. A second optical signal can be generated at a second end of the optical fiber segment at a third time in response to the detection of the first optical signal. The second optical signal can be detected at the first end of the optical fiber segment at a fourth time. A length of the optical fiber segment can be determined based on a difference between the second time and the first time, a difference between the third time and the second time, and a difference between the fourth time and the third time.Type: ApplicationFiled: October 15, 2007Publication date: April 16, 2009Applicant: CISCO TECHNOLOGY INC.Inventors: Stefano Piciaccia, Fabrizio Forghieri, Ornan Gerstel, Gabriele Maria Galimberti -
Publication number: 20090003837Abstract: An economic way of determining the chromatic dispersion along a link of a DWDM network is provided. A transmitter modulates the output signals of two lasers operating at two different wavelengths and the modulated output signals are sent into the link. Detectors at each one of a plurality of detection sites along the link determine a phase difference in modulation between the output signals of the two lasers. The chromatic dispersion for each detection site can be calculated from the modulation frequency and determined phase differences at that site.Type: ApplicationFiled: May 23, 2007Publication date: January 1, 2009Applicant: CISCO TECHNOLOGY, INC.Inventors: Stefano Piciaccia, Fabrizio Forghieri
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Publication number: 20080259968Abstract: Methods and apparatus for varying the transmission rate of a signal transmitted within a dense wavelength division multiplexing (DWDM) system or network are disclosed. According to one aspect of the present invention, a method includes obtaining a first signal and determining a transmission rate associated with the first. If it is determined that the transmission rate is a first rate, the method includes processing the first signal as having a first transmission format and the first rate. Alternatively, it is determined that the transmission rate is not the first rate and is a second rate, the method includes processing the first signal as having a second transmission format and a second rate.Type: ApplicationFiled: April 17, 2007Publication date: October 23, 2008Applicant: CISCO TECHNOLOGY, INC.Inventors: FABRIZIO FORGHIERI, LUCA DELLA CHIESA
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Patent number: 7231108Abstract: An adaptive dispersion compensation system that also achieves optical amplification by inducing Raman amplification effects in dispersion compensating fiber. This amplification/chromatic dispersion compensation architecture may be applied, e.g., at the end of an all-optical link, or an intermediate points along the link. By varying the length of dispersion compensating fiber used and the pump power, one may accommodate a wide range of dispersion compensation requirements as determined in the field. This scheme also provides all of the advantages typically provided by the use of Raman amplification.Type: GrantFiled: February 22, 2006Date of Patent: June 12, 2007Assignee: Cisco Technology, Inc.Inventors: Fabrizio Di Pasquale, Fabrizio Forghieri
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Publication number: 20060126998Abstract: An adaptive dispersion compensation system that also achieves optical amplification by inducing Raman amplification effects in dispersion compensating fiber. This amplification/chromatic dispersion compensation architecture may be applied, e.g., at the end of an all-optical link, or an intermediate points along the link. By varying the length of dispersion compensating fiber used and the pump power, one may accommodate a wide range of dispersion compensation requirements as determined in the field. This scheme also provides all of the advantages typically provided by the use of Raman amplification.Type: ApplicationFiled: February 22, 2006Publication date: June 15, 2006Applicant: CISCO TECHNOLOGY, INC.Inventors: Fabrizio Di Pasquale, Fabrizio Forghieri
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Patent number: 7038842Abstract: Raman amplifiers with improved signal to noise ratio and four-wave mixing product suppression are provided. In one embodiment, both co-propagating and counter-propagating pump energy are employed to cause Raman amplification effects within a fiber. Improved Raman amplification performance including improved four-wave mixing product suppression facilitates longer distance transmission without regeneration of optical signals and/or denser WDM channel spacings.Type: GrantFiled: February 25, 2005Date of Patent: May 2, 2006Assignee: Cisco Technology, Inc.Inventors: Enrico Griseri, Fabrizio Forghieri
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Patent number: 7024071Abstract: An adaptive dispersion compensation system that also achieves optical amplification by inducing Raman amplification effects in dispersion compensating fiber. This amplification/chromatic dispersion compensation architecture may be applied, e.g., at the end of an all-optical link, or an intermediate points along the link. By varying the length of dispersion compensating fiber used and the pump power, one may accommodate a wide range of dispersion compensation requirements as determined in the field. This scheme also provides all of the advantages typically provided by the use of Raman amplification.Type: GrantFiled: May 24, 2004Date of Patent: April 4, 2006Assignee: Cisco Technology, Inc.Inventors: Fabrizio Di Pasquale, Fabrizio Forghieri
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Publication number: 20050157378Abstract: Raman amplifiers with improved signal to noise ratio and four-wave mixing product suppression are provided. In one embodiment, both co-propagating and counter-propagating pump energy are employed to cause Raman amplification effects within a fiber. Improved Raman amplification performance including improved four-wave mixing product suppression facilitates longer distance transmission without regeneration of optical signals and/or denser WDM channel spacings.Type: ApplicationFiled: February 25, 2005Publication date: July 21, 2005Applicant: Cisco Technology, Inc.Inventors: Enrico Griseri, Fabrizio Forghieri
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Patent number: 6867905Abstract: Raman amplifiers with improved signal to noise ratio and four-wave mixing product suppression are provided. In one embodiment, both co-propagating and counter-propagating pump energy are employed to cause Raman amplification effects within a fiber. Improved Raman amplification performance including improved four-wave mixing product suppression facilitates longer distance transmission without regeneration of optical signals and/or denser WDM channel spacings.Type: GrantFiled: July 5, 2001Date of Patent: March 15, 2005Assignee: Cisco Technolog, Inc.Inventors: Enrico Griseri, Fabrizio Forghieri