Tyco Electronics Subsea Communications LLC

Tyco Telecommunications (us) Inc.

Subcom, LLC

Jin-Xing Cai

Morten Nissov

Alexei N Pilipetskii

Yi Cai

Dmitri G Foursa

Carl R Davidson

Hongbin Zhang

Georg Heinrich Mohs

Neal S Bergano

Maxim A Bolshtyansky

Hussam G Batshon

Yu Sun

Matthew V Mazurczyk

Carl Davidson

Apparatus, systems, and techniques for extending distributed acoustic sensing (DAS) range in undersea optical cables over multiple spans, as well as providing span-specific DAS information, are provided.

Extending dynamic acoustic sensing range and localization in undersea cables using loopbacks

An optical subcarrier multiplex system. An input data signal is jointly coded with at least one forward error correction (FEC) code before symbol mapping and before subcarrier modulation. Joint FEC coding mitigates non-uniform subcarrier performance.

Optical subcarrier multiplex system with joint forward error correction coding

In general, optical communication systems and methods may generate higher-level nQAM from nQAM signals using one or more delay line interferometers (DLIs) arranged in various configurations. The nQAM signals may be generated by a lower-level modulator, such as a BPSK modulator, QPSK modulator or lower-level QAM modulator, with binary driving signals. Different parameters of the DLIs, such as free spectral range (FSR), phase shift, and amplitude imbalance, may be selected to accomplish the desired higher-level nQAM depending upon the nQAM signal.

Generating higher-level quadrature amplitude modulation (QAM) using a delay line interferometer and systems and methods incorporating same

A system and method for soft decision forward error correction (FEC) decoding may be used to determine a possible error in a differential detection signal, for example, in a DPSK system. The system and method uses the constructive and destructive signals from a demodulator to provide an error locating signal. Using the error locating signal, the system and method converts the differential detection signal into a soft decision signal including multi-level soft values.

System and method for forward error correction decoding using soft information

In general, optical communication systems and methods may implement a vestigial phase shift keying (PSK) modulation format to enable relatively high transmission rates with closer channel spacing and improved signal detection in a WDM optical communication system. A PSK modulated signal may be correlated with a phase shift, for example, using a delay line interferometer (DLI), to generate a vestigial PSK signal, which may be pre-filtered, combined, and transmitted in the WDM system. The correlation with a phase shift compresses and shifts the signal spectrum such that intersymbol interference (ISI) length may be reduced with minimal increase in the bit error rate (BER) when the vestigial PSK signal is detected.

Vestigial phase shift keying modulation and systems and methods incorporating same

Polarization multiplexing with different differential phase shift keying (DPSK) schemes generally uses DPSK modulated signals modulated using different DPSK modulation schemes and combined with orthogonal polarizations relative to each other. The different DPSK modulation schemes may use different DPSK phase shifts to represent data, such as a regular DPSK modulation scheme and a &#x3c0;/2 DPSK modulation scheme. By using different DPSK modulation schemes to represent data on the orthogonally polarized signals, the DPSK demodulators may effectively separate the orthogonally polarized signals using the property of the DPSK receivers. To optimize performance, the DPSK modulated signals may also be bit-interleaved when combined with orthogonal polarization.

Polarization multiplexing with different DPSK modulation schemes and system incorporating the same

A system and method for mitigating dispersion slope is capable of reducing the performance impact on an optical communication system caused by dispersion slope. The system and method receives an optical signal, demultiplexes the optical signal and optically filters the demultiplexed optical signals. The optical filters may have a bandwidth that is wide with respect to the demultiplexed optical signals and narrow with respect to the original optical signal.

System and method for mitigating dispersion slope in an optical communication system

A WDM optical transmission system and method uses slope compensation at the transmit terminal and/or the receive terminal. The system and method may be used with modulation formats with a short pulse width and a broad optical spectrum.

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Morganville, NJ, United States of America

Jin-Xing Cai