Patents by Inventor Fenghai Liu
Fenghai Liu 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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Publication number: 20130163986Abstract: The present application describes methods and systems that improve the optical signal to noise ratio performance of an optical network without the need to vary the free spectral range associated with a differential interferometer. This is achieved by varying an electrical bandwidth of an electronic device associated with the receiver. For example, the electrical bandwidth may vary in inverse proportion to the combined effective optical bandwidth of the transmission line carrying the optical signal. The techniques described herein a applicable to a wide variety of modulation formats, including mPSK, DPSK, DmPSK, PDmPSK, mQAM, ODB, and other direct-detection formats. Using the techniques described herein, the optical signal to noise ratio and bit error ratio performance of the optical network is improved without the need to provide costly and complex differential interferometers whose free spectral range is variable.Type: ApplicationFiled: April 15, 2011Publication date: June 27, 2013Inventors: Pavel Mamyshev, John Leonard Zyskind, Seo Yeon Park, Fenghai Liu
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Publication number: 20110280588Abstract: An optical receiver includes a demodulator having a delay interferometer comprising an optical input that receives a phase modulated optical signal from a bandwidth limited transmission system. The delay interferometer has a free spectral range that is larger than a symbol rate of the phase modulated optical signal by an amount that improves receiver performance. The receiver also includes a differential detector having a first and a second photodetector. The first photodetector is optically coupled to the constructive optical output of the delay interferometer. The second photodetector is optically coupled to the destructive optical output of the delay interferometer. The differential detector combines a first electrical detection signal generated by the first photodetector and a second electrical detection signal generated by the second photodetector to generate an electrical reception signal.Type: ApplicationFiled: April 14, 2011Publication date: November 17, 2011Inventors: Benny MIKKELSEN, Pavel MAMYSHEV, Christian RASMUSSEN, Fenghai LIU
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Patent number: 7949261Abstract: An optical receiver includes a demodulator having a delay interferometer comprising an optical input that receives a phase modulated optical signal from a bandwidth limited transmission system. The delay interferometer has a free spectral range that is larger than a symbol rate of the phase modulated optical signal by an amount that improves receiver performance. The receiver also includes a differential detector having a first and a second photodetector. The first photodetector is optically coupled to the constructive optical output of the delay interferometer. The second photodetector is optically coupled to the destructive optical output of the delay interferometer. The differential detector combines a first electrical detection signal generated by the first photodetector and a second electrical detection signal generated by the second photodetector to generate an electrical reception signal.Type: GrantFiled: April 25, 2007Date of Patent: May 24, 2011Assignee: Mintera CorporationInventors: Benny Mikkelsen, Pavel Mamyshev, Christian Rasmussen, Fenghai Liu
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Patent number: 7366425Abstract: Different techniques for generating spectrally efficient carrier-suppressed modulated optical signals, also known as “phase-shaped binary transmission” (PSBT) signals, employ electrical components that generate only 2-level or binary signals, in contrast to techniques that require 3-level electrical drivers. The PSBT modulators can be used with return-to-zero (RZ) modulators for generating RZ-PSBT signals, which have the characteristic of even greater spectral efficiency than NRZ PSBT signals. The technique is generalized to RZ signals with an arbitrary phase difference between pulses. These signals can be generated by shifting the central (carrier) frequency of an RZ modulated optical signal, which can be done using a certain phase modulation or using spectral filtering with a passband offset from the center (carrier) frequency of the modulated optical signal, and the signals can also be generated by phase modulation at a frequency lower than the signaling rate of the modulated signal.Type: GrantFiled: March 11, 2003Date of Patent: April 29, 2008Assignee: Mintera CorporationInventors: Pavel V. Mamyshev, Christian J. Rasmussen, Benny P. Mikkelsen, Fenghai Liu
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Publication number: 20070196110Abstract: An optical receiver includes a demodulator having a delay interferometer comprising an optical input that receives a phase modulated optical signal from a bandwidth limited transmission system. The delay interferometer has a free spectral range that is larger than a symbol rate of the phase modulated optical signal by an amount that improves receiver performance. The receiver also includes a differential detector having a first and a second photodetector. The first photodetector is optically coupled to the constructive optical output of the delay interferometer. The second photodetector is optically coupled to the destructive optical output of the delay interferometer. The differential detector combines a first electrical detection signal generated by the first photodetector and a second electrical detection signal generated by the second photodetector to generate an electrical reception signal.Type: ApplicationFiled: April 25, 2007Publication date: August 23, 2007Applicant: MINTERA CORPORATIONInventors: Benny Mikkelsen, Pavel Mamyshev, Christian Rasmussen, Fenghai Liu
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Publication number: 20030218790Abstract: A high speed digital optical transmission system that improves data transmission performance in both linear and nonlinear system environments. The high speed optical transmission system includes a laser for generating a CW light beam, and a data modulator for modulating the CW light beam in response to an electrical NRZ data signal to generate a modulated NRZ optical signal with positive chirp. The bias point of the data modulator is obtained by increasing the bias offset relative to quadrature while maintaining the voltage corresponding to a 0 bit at a predetermined level. The bias point allows the data modulator to be operated so that the chirp of the modulated NRZ optical signal is positive for most of each bit time slot.Type: ApplicationFiled: March 17, 2003Publication date: November 27, 2003Applicant: MINTERA CORPORATIONInventors: Benny P. Mikkelsen, Christian J. Rasmussen, Tina Fjelde, Fenghai Liu, Pavel V. Mamyshev, David Wolfson, John E. Kaufmann
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Publication number: 20030175036Abstract: Different techniques for generating spectrally efficient carrier-suppressed modulated optical signals, also known as “phase-shaped binary transmission” (PSBT) signals, employ electrical components that generate only 2-level or binary signals, in contrast to techniques that require 3-level electrical drivers. The PSBT modulators can be used with return-to-zero (RZ) modulators for generating RZ-PSBT signals, which have the characteristic of even greater spectral efficiency than NRZ PSBT signals. The technique is generalized to RZ signals with an arbitrary phase difference between pulses. These signals can be generated by shifting the central (carrier) frequency of an RZ modulated optical signal, which can be done using a certain phase modulation or using spectral filtering with a passband offset from the center (carrier) frequency of the modulated optical signal, and the signals can also be generated by phase modulation at a frequency lower than the signaling rate of the modulated signal.Type: ApplicationFiled: March 11, 2003Publication date: September 18, 2003Applicant: MINTERA CORPORATIONInventors: Pavel V. Mamyshev, Christian J. Rasmussen, Benny P. Mikkelsen, Fenghai Liu