Tyco Electronics Subsea Communications LLC

Tyco Telecommunications (us) Inc.

Jerzy R Domagala

Yi Cai

Alexei N Pilipetskii

Franklin Webb Kerfoot, Iii

Greg Valvo

Gregory Valvo

Franklin Webb Kerfoot Iii

A soft decision threshold control system and method may be used with a forward error correction (FEC) scheme to adjust or tune one or more soft decision thresholds in response to one or more bit value averages for the threshold(s) and in response to a bit error rate (BER). The bit value average for a soft decision threshold generally refers to an average number of binary values (e.g., logic ones and/or zeros) occurring in a bit stream detected using the soft decision threshold. For different BER levels in a particular system, for example, one or more of the soft decision thresholds may have a predetermined bit value average, which has been determined to provide a certain level of performance (e.g., an optimum performance). Thus, one or more of the soft decision thresholds may be adjusted such that the bit value averages for the soft decision thresholds are adjusted as a function of the BER. The settings of the soft decision thresholds may also be adjusted in response to changes in a signal amplitude of the input signal being detected.

Soft decision threshold control in a signal receiver using soft decision error correction

A receiver for a differentially phase shift keying formatted optical signal, such as an RZ-DPSK formatted optical signal. Dither control loops are provided for controlling path length in a demodulator and/or for controlling the center wavelength of an optical band pass filter. A feedback loop is provided for controlling the gain of a pre-amplifier, and a method of protecting against optical transients by disabling a pre-amplifier is also provided. A preset delay may be provided to compensate for the differential delay in paths associated with the demodulator arms. When the signal is an RZ-DPSK modulated signal, a clock for retiming data from the optical signal may be derived from a signal on the data path.

Optical receiver including a system and method of controlling gain of an optical amplifier

Optical receiver

An apparatus and method for decision threshold control in an optical signal receiver. A forward error correction (FEC) decoder provides a feedback signal representative of corrected errors. The decision threshold is adjusted to balance a number of corrected ones and zeros.

Method and apparatus for decision threshold control in an optical signal receiver

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Red Bank, NJ, United States of America

Jerzy R Domagala