Abstract: Feed-forward and feedback strategies are used to control local oscillator power and transimpedance amplifier gain in a high-speed coherent optical receiver.
Type:
Grant
Filed:
September 15, 2011
Date of Patent:
July 1, 2014
Assignee:
Opnext Subsystems, Inc.
Inventors:
Sunil Kumar Singh Khatana, George Zarris
Abstract: I/Q data skew in a QPSK modulator may be detected by sending identical or complementary data streams to I and Q channel PSK modulators, setting the relative carrier phase between I and Q to zero or ?, and monitoring the average QPSK output power, where the data streams sent to the I and Q channels include streams of alternating ones and zeroes.
Abstract: Digital timing error detection systems and techniques are described. The described techniques are independent of polarization and differential-group-delay and are used to perform timing recovery of polarization-multiplexed coherent optical systems.
Abstract: Patterns detected by a low-speed receiver at the output of a high-speed multiplexer are used to determine when multiplexer input lanes are deskewed.
Abstract: An adaptive-equalizer initialization system performs three functions: frequency offset estimation, taps estimation for chromatic dispersion filters, and taps initialization for an adaptive equalizer. The system contains hardware FFT and peak detector units that sense a pure tone that marks the beginning of a known, short data sequence.
Type:
Grant
Filed:
October 28, 2010
Date of Patent:
September 10, 2013
Assignee:
Opnext Subsystems, Inc.
Inventors:
Andrew Wagner, Christian Malouin, Theodore J. Schmidt
Abstract: Coherent optical receiver performance is optimized and made adaptable to changing optical channel conditions by providing feedback loops to adjust receiver parameters based on measured receiver performance.
Abstract: I/Q data skew in a QPSK modulator may be detected by sending identical or complementary data streams to I and Q channel PSK modulators, setting the relative carrier phase between I and Q to zero or ?, and monitoring the average QPSK output power, where the data streams sent to the I and Q channels include pseudorandom streams of ones and zeroes.
Abstract: Feed-forward and feedback strategies are used to control local oscillator power and transimpedance amplifier gain in a high-speed coherent optical receiver.
Type:
Application
Filed:
September 15, 2011
Publication date:
March 21, 2013
Applicant:
OPNEXT SUBSYSTEMS, INC.
Inventors:
Sunil Kumar Singh Khatana, George Zarris
Abstract: Digital timing error detection systems and techniques are described. The described techniques are independent of polarization and differential-group-delay and are used to perform timing recovery of polarization-multiplexed coherent optical systems.
Abstract: I/Q data skew in a QPSK modulator may be detected by sending identical or complementary data streams to I and Q channel PSK modulators, setting the relative carrier phase between I and Q to zero or ?, and monitoring the average QPSK output power, where the data streams sent to the I and Q channels include streams of alternating ones and zeroes.
Abstract: Patterns detected by a low-speed receiver at the output of a high-speed multiplexer are used to determine when multiplexer input lanes are deskewed.
Abstract: I/Q data skew in a QPSK modulator may be detected by sending identical or complementary data streams to I and Q channel PSK modulators, setting the relative carrier phase between I and Q to zero or ?, and monitoring the average QPSK output power, where the data streams sent to the I and Q channels include pseudorandom streams of ones and zeroes.
Abstract: Apparatus and methods for receiving and processing optical signals carrying symbols that represent data, including an optical receiver having fractional sampling analog-to-digital conversion and interpolation timing recovery synchronization for processing an optical signal.
Type:
Grant
Filed:
October 28, 2009
Date of Patent:
August 14, 2012
Assignee:
Opnext Subsystems, Inc.
Inventors:
Andrew Wagner, Christian Malouin, Theodore J. Schmidt
Abstract: Apparatus and methods for optimizing the interplay between the sampling rate of an ADC of a receiver system and a bandwidth of analog anti-aliasing filters are described. The described technology can be used to mitigate aliasing for receiver systems that operate at fractional sampling rates by optimizing a bandwidth of optical and electrical filters included in the receiver systems.
Type:
Application
Filed:
March 25, 2011
Publication date:
September 29, 2011
Applicant:
OPNEXT SUBSYSTEMS, INC.
Inventors:
Andrew Wagner, Christian Malouin, Theodore J. Schmidt
