Tsutomu Tajima

Terabit/s Nyquist Superchannels in High Capacity Fiber Field Trials Using DP-16QAM and DP-8QAM Modulation Formats

We report the results of two field trials aimed at achieving high fiber capacity over regional and long-haul distances. In the first trial, 41 superchannels with digital Nyquist pulse-shaping were generated and tightly packed to fill up both C-band and L-band. Each subcarrier was modulated with 24.8-Gbaud dual-polarization 16 quadrature amplitude modulation (DP-16QAM) data. The signal carrying net 54.2 Tb/s data was transmitted over 634 km of dispersion uncompensated field-installed standard single mode fiber with the aid of hybrid EDFA and Raman amplification and digital coherent detection. In the second trial for long-haul distances, we extended the transmission distance over 1,822 km. This increase in reach was achieved by reducing the net total capacity to 40.5 Tb/s and modulating the signals with dual-polarization 8 quadrature amplitude modulation (DP-8QAM) Nyquist carrier modulation. A novel rate-adaptive low-density parity-check coding was employed, so that the transmitted channels can exhibit different code rates, adapted by the concatenation of hard-decision and soft-decision forward error correcting codes for enhancing error-correction capability. To the best of our knowledge, we achieved the highest field trial capacity to date at 54.2 Tb/s in regional distances. Furthermore, in long-haul applications, the reported capacity × distance product of 73.79 Pb/s·km is the highest to date.

Terabit/s optical superchannel with flexible modulation format for dynamic distance/route transmission

A superchannel transmitter with fixed 1-Tb/s net data rate and flexible modulation format suitable for dynamic distance/route transmission is proposed. System reach between 800 and 6,000km was achieved with spectral efficiency from 6.15b/s/Hz and 3.33b/s/Hz.

High capacity field trials of 40.5 Tb/s for LH distance of 1,822 km and 54.2 Tb/s for regional distance of 634 km

40.5 Tb/s over 1,822 km and 54.2 Tb/s over 634 km field SSMF was realized using 41 Nyquist rate DP-8QAM and DP-16QAM superchannels. They are the highest field capacities for long-haul and regional distances achieved so far.

High-Capacity Fiber Field Trial Using Terabit/s All-Optical OFDM Superchannels With DP-QPSK and DP-8QAM/DP-QPSK Modulation

We report the results of two separate field trials aimed to achieve high fiber capacity over long-haul distances. In the first trial, 22 all-optical orthogonal frequency-division multiplexing superchannels with hybrid dual-polarization 8 quadrature amplitude modulation and dual-polarization quadrature phase-shift-keying (DP-QPSK) modulation were generated using a novel flexible format superchannel transmitter design. The signal carrying net 21.7 Tb/s data was transmitted over 1503 km of dispersion uncompensated field-installed standard single-mode fiber with the aid of hybrid Raman and erbium-doped fiber amplifier (EDFA) amplification and digital coherent detection. In the second trial, we extended the transmission distance to over 2531 km of field fiber using only EDFA for loss compensation. The increase in reach was achieved by reducing the net total data rate to 16.2 Tb/s and modulating the optical superchannel subcarriers with DP-QPSK only. To the best of our knowledge, we achieved the highest capacity field trial record to date at 21.7 Tb/s in the first trial, while the achieved capacity-distance product of 40.9 Pb/s ·km in the second trial is also the highest reported to date.

112Gb/s optical transponder with PM-QPSK and coherent detection employing parallel FPGA-based real-time digital signal processing, FEC and 100GbE Ethernet interface

We demonstrate 112Gb/s transmission using PM-QPSK format and FPGA-based real-time digital signal processing. By employing framed processing architecture for polarization demultiplexing and carrier phase estimation, stable operation of error free after FEC and wide frequency offset have been achieved.

Real-time 400G superchannel transmission using 100-GbE based 37.5-GHz spaced subcarriers with optical Nyquist shaping over 3,600-km DMF link

400G superchannel with four parallel 100-GbE subcarriers is successfully transmitted in real-time over 3600-km of DMF link using 150-GHz bandwidth. Optical Nyquist shaping is employed to reduce performance penalty induced by sharp optical filtering.

Mixed Line-Rate Transmission (112-Gb/s, 450-Gb/s, and 1.15-Tb/s) Over 3560 km of Field-Installed Fiber With Filterless Coherent Receiver

We report the first superchannel field experiment where two multicarrier signals at 450 Gb/s and 1.15 Tb/s are copropagated with 112-Gb/s neighbors over 45 × 79.1 km spans of field-installed fiber with erbium-doped fiber amplifiers after each span. The superchannels use zero-guard interval all-optical orthogonal frequency-division multiplexing, with each optically generated subcarrier modulated by dual-polarization quadriphase-shift-keying signals (DP-QPSK). The heterogeneous data-rate channels are aggregated using wavelength selective switch in a flexible grid wavelength-division multiplexing architecture. The net spectral efficiencies of the channels vary from 2 b/s/Hz for the 112-Gb/s channels, to 3.33 b/s/Hz for the 1.15-Tb/s superchannel. We demonstrate that any of the signals can be detected using a common filterless digital coherent receiver. In particular, tuning a local oscillator laser midway between two optically generated subcarriers enables the coherent receiver (with proper signal-processing algorithm) to demodulate two subcarriers in one data capture. This allows flexible downconversion across the whole signal band. Our results show that superchannels can coexist harmoniously with 100 G DP-QPSK signals. Even though the superchannels use the same modulation format per subcarrier as the 100 G signals, the absence of guard bands enables higher spectral efficiency that is achievable with single-carrier modulation with minimal sacrifice in reach.

Demonstration of OpenFlow-Enabled Traffic and Network Adaptive Transport SDN

We experimentally demonstrate the first OpenFlow-enabled transport SDN that performs multi-flow switching by cross-layer optimization and configuring all major hardware elements, including adaptive EDFA-Raman amplifiers, multi-degree superchannel transponders, and flexible grid switching nodes.

21.7 Tb/s field trial with 22 DP-8QAM/QPSK optical superchannels over 1,503-km of installed SSMF

To the best of our knowledge, this is the highest capacity field trial completed to date at 21.7-Tb/s. 22 optical superchannels with flexible modulation formats were transmitted over 1,503-km installed SSMF using digital coherent detection.

16.2-Tb/s field trial over 2,531-km of installed SSMF with DP-QPSK optical superchannels

We report 16.2-Tb/s transmission over 32×79.1-km spans of field fiber using optical superchannels with DP-QPSK modulated subcarriers. The achieved capacity-distance product of 40.9-Pb/s-km is the highest reported to date for a field trial.