Patents Assigned to Stratalight Communication, Inc.
  • Patent number: 7437080
    Abstract: An optical transmission system having optical transmit and receive filters having passbands adjusted or selected for opposite and equal wavelength offsets from the optical wavelength of a carrier or the channel center wavelength.
    Type: Grant
    Filed: February 3, 2005
    Date of Patent: October 14, 2008
    Assignee: Stratalight Communications, Inc.
    Inventors: Theodore J. Schmidt, Anhui H. Liang
  • Patent number: 7415213
    Abstract: An optical receiver having compensation for signal level transients. The receiver includes an OE converter, a transient threshold compensator, a threshold combiner and a CDR system. The OE converter receives the incoming optical signal and provides a modulated electrical signal having a high speed response for tracking the modulation on the optical signal and an averaged electrical signal having a moderate speed response for tracking changes in the average level of the optical signal. The transient threshold compensator processes the averaged electrical signal for providing a transient feedforward adjustment. The threshold combiner combines the transient feedforward adjustment with a lower speed BER feedback threshold adjustment for providing a decision threshold signal. The CDR system uses the decision threshold signal for recovering a clock, providing the BER feedback threshold adjustment, and estimating the data carried by the modulation.
    Type: Grant
    Filed: November 24, 2004
    Date of Patent: August 19, 2008
    Assignee: Stratalight Communications, Inc.
    Inventor: Gary Wang
  • Patent number: 7287213
    Abstract: A circuit using modular based parallel processing calculates the cumulative parity of a binary number input sequence. The circuit is used, for example, to implement a precoder for an optical duobinary transmission system. The design permits a relatively low-speed circuit to be used as the precoder before a time-division multiplexer. The parallel circuit can be scalable to process a very large number of sets of parallel binary data by the usage of two basic modules, namely, a parity module and a delay module.
    Type: Grant
    Filed: April 24, 2001
    Date of Patent: October 23, 2007
    Assignee: Stratalight Communications, Inc.
    Inventors: Ricky Keang-Po Ho, Joseph M. Kahn
  • Patent number: 7280767
    Abstract: An optical duobinary transmitter. The transmitter uses a half-rate precoder, half-rate non-linear modulation drive circuits and a multiplex modulator for generating duobinary modulation on an optical signal from which full-rate data can be detected without decoding. The intensity of the optical signal is modulated to be zero between data symbols.
    Type: Grant
    Filed: August 26, 2004
    Date of Patent: October 9, 2007
    Assignee: StrataLight Communications, Inc.
    Inventors: Keangpo Ricky Ho, Ross Alexander Saunders
  • Patent number: 7162163
    Abstract: A method and apparatus for reducing nonlinear phase noise that is induced in an optical transmission system by the interaction of optical amplifier noise and Kerr effect. The apparatus includes an intensity-scaled nonlinear phase noise compensator. The phase noise compensator reduces the nonlinear phase noise by applying a scaled differential signal strength estimate to estimated differential quadrature components or an estimated differential phase for providing a phase noise compensated representation.
    Type: Grant
    Filed: January 18, 2006
    Date of Patent: January 9, 2007
    Assignee: StrataLight Communications, Inc.
    Inventors: Keangpo Ho, Joseph Mardell Kahn
  • Patent number: 7133620
    Abstract: A method and apparatus for reducing nonlinear phase noise that is induced in an optical transmission system by the interaction of optical amplifier noise and Kerr effect. The apparatus includes an intensity-scaled non-linear phase noise compensator. The phase noise compensator provides a phase noise compensated representation of a differential frequency by combining a measured differential frequency with a scaled differential signal strength estimate. The scale factor is derived from the number of spans in the transmission system.
    Type: Grant
    Filed: January 18, 2006
    Date of Patent: November 7, 2006
    Assignee: Stratalight Communication, Inc.
    Inventors: Keangpo Ho, Joseph Mardell Kahn
  • Patent number: 7013089
    Abstract: A method and apparatus for reducing nonlinear phase noise that is induced in an optical transmission system by the interaction of optical amplifier noise and Kerr effect. The apparatus includes an intensity-scaled nonlinear phase noise compensator. The phase noise compensator reduces the nonlinear phase noise by rotating a phase estimate by a scaled signal strength estimate for the optical signal or by comparing a complex estimate of the optical signal to curved regions having scaled nonlinear decision boundaries. The scale factor is derived from the number of spans in the transmission system.
    Type: Grant
    Filed: April 30, 2004
    Date of Patent: March 14, 2006
    Assignee: StrataLight Communications, Inc.
    Inventors: Keangpo Ho, Joseph Mardell Kahn
  • Patent number: 6915084
    Abstract: A method and apparatus for reducing nonlinear phase noise that is induced in an optical transmission system by the interaction of optical amplifier noise and Kerr effect. The apparatus includes an intensity-scaled nonlinear phase noise compensator. The phase noise compensator reduces the nonlinear phase noise by rotating a phase estimate by a scaled signal strength estimate for the optical signal or by comparing a complex estimate to curved regions having scaled nonlinear decision boundaries. The scale factor is derived from the number of spans in the transmission system. Another embodiment of the phase noise compensator uses the scaled signal strength for re-modulating an optical signal.
    Type: Grant
    Filed: September 3, 2002
    Date of Patent: July 5, 2005
    Assignee: StrataLight Communications, Inc.
    Inventors: Keangpo Ho, Joseph Mardell Kahn
  • Patent number: 6804472
    Abstract: An optical duobinary transmitter. The transmitter uses a half-rate precoder, half-rate non-linear modulation drive circuits and a multiplex modulator for generating duobinary modulation on an optical signal from which full-rate data can be detected without decoding.
    Type: Grant
    Filed: November 18, 2002
    Date of Patent: October 12, 2004
    Assignee: StrataLight Communications, Inc.
    Inventor: Keangpo Ricky Ho
  • Patent number: 6690894
    Abstract: Methods and apparatus are described to transmit and receive information encoded in multilevel optical signals that take on at least three intensity levels. Intensity levels of a transmitted multilevel optical signal are optimized to minimize a transmitted optical power required to achieve a specified decision error probability, taking account of an arbitrary admixture of impairments, including signal-dependent noise, signal-independent noise, a finite transmitter extinction ratio, and intersymbol interference. The optimizations described are implemented using analytical or numerical techniques, depending on the admixture of impairments, and can be used to achieve equal or unequal decision error probabilities at a set of decision thresholds.
    Type: Grant
    Filed: May 14, 2001
    Date of Patent: February 10, 2004
    Assignee: StrataLight Communications, Inc.
    Inventors: Keangpo Ho, Joseph Mardell Kahn
  • Patent number: 6592274
    Abstract: Methods and apparatus to transmit and receive information bits encoded in duobinary, multilevel pulse-amplitude-modulated (PAM) optical signals are described. The transmitted optical signal has a narrow optical spectrum and a low symbol rate. Information bits are encoded in a M-ary PAM symbol sequence, where M≧2. The PAM symbol sequence is input to a finite-state machine, which yields an encoded sequence that changes sign between two symbol intervals when the encoded sequence takes on a nominally zero value during an odd number of intervening symbol intervals. The encoded sequence is lowpass filtered and modulated onto an optical electric field. The receiver processes a received optical electric field to obtain an electrical signal proportional to the received optical intensity, and performs M-ary symbol-by-symbol decisions to recover the transmitted information bits, without potential error propagation.
    Type: Grant
    Filed: June 7, 2002
    Date of Patent: July 15, 2003
    Assignee: StrataLight Communications, Inc.
    Inventors: Joseph Mardell Kahn, Keangpo Ho
  • Patent number: 6490069
    Abstract: Methods and apparatus to transmit and receive information bits encoded in duobinary, multilevel pulse-amplitude-modulated (PAM) optical signals. The transmitted optical signal has a narrow optical spectrum and a low symbol rate. Information bits are encoded in a M-ary PAM symbol sequence, where M≳2. A subtraction-based encoder precodes and duobinary filters the M-ary PAM symbol sequence, yielding an encoded sequence. The encoded sequence is lowpass filtered and modulated onto an optical electric field. The receiver processes a received optical electric field to obtain an electrical signal proportional to the received optical intensity, and performs M-ary symbol-by-symbol decisions to recover the transmitted information bits, without potential error propagation.
    Type: Grant
    Filed: January 29, 2001
    Date of Patent: December 3, 2002
    Assignee: StrataLight Communications, Inc.
    Inventors: Joseph Mardell Kahn, Keangpo Ho
  • Patent number: 6445476
    Abstract: Methods and apparatus to transmit and receive information bits encoded in duobinary, multilevel pulse-amplitude-modulated (PAM) optical signals are described. The transmitted optical signal has a narrow optical spectrum and a low symbol rate. Information bits are encoded in a M-ary PAM symbol sequence, where M≧3. The subsequence-based encoder decomposes the PAM symbol sequence into M1 subsequences, precodes each subsequence, performs duobinary filtering on each precoded subsequence, and forms a weighted sum of the duobinary precoded subsequences. The weighted sum of duobinary precoded subsequences is lowpass filtered and modulated onto an optical electric field. The receiver processes a received optical electric field to obtain an electrical signal proportional to the received optical intensity, and performs M-ary symbol-by-symbol decisions to recover the transmitted information bits, without potential error propagation.
    Type: Grant
    Filed: January 29, 2001
    Date of Patent: September 3, 2002
    Assignee: StrataLight Communications, Inc.
    Inventors: Joseph Mardell Kahn, Keangpo Ho
  • Patent number: 6424444
    Abstract: Methods and apparatus to transmit and receive information bits encoded in duobinary, multilevel pulse-amplitude-modulated (PAM) optical signals are described. The transmitted optical signal has a narrow optical spectrum and a low symbol rate. Information bits are encoded in a M-ary PAM symbol sequence, where M≧2. The PAM symbol sequence is input to a finite-state machine, which yields an encoded sequence that changes sign between two symbol intervals when the encoded sequence takes on a nominally zero value during an odd number of intervening symbol intervals. The encoded sequence is lowpass filtered and modulated onto an optical electric field. The receiver processes a received optical electric field to obtain an electrical signal proportional to the received optical intensity, and performs M-ary symbol-by-symbol decisions to recover the transmitted information bits, without potential error propagation.
    Type: Grant
    Filed: January 29, 2001
    Date of Patent: July 23, 2002
    Assignee: StrataLight Communications, Inc.
    Inventors: Joseph Mardell Kahn, Keangpo Ho