Matt Mazurczyk

200 Gb/s and dual-wavelength 400 Gb/s transmission over transpacific distance at 6 b/s/Hz spectral efficiency

We transmit 106×200 Gb/s channels over 10,290 km at 6.0 b/s/Hz enabled by Nyquist spectral shaping and nonlinearity compensation. We also transmit 53×400 Gb/s channels over 9,200 km detecting two 200 Gb/s wavelengths simultaneously using a wideband receiver.

Spectral Shaping in Long Haul Optical Coherent Systems With High Spectral Efficiency

One of the main obstacles faced when decreasing channel spacing in optical wavelength division multiplexing (WDM) systems is the linear crosstalk resulting from spectral overlap between neighboring channels. Methods of reducing channel bandwidth and corresponding crosstalk using optical pre-filtering are reviewed along with the limitations of these techniques. High speed transmitter side digital signal processing (DSP) and digital-to-analog converters enable the use of more powerful techniques that precisely shape and limit the bandwidth of the transmitted optical signal. These techniques allow channel spacing to be reduced to nearly the theoretical minimum Nyquist spacing with only negligible crosstalk penalty. We review well known principles of linear modulation theory and apply them to coherent optical transmission systems to describe the desired channel transmit spectra along with the associated transmit and receive DSP. The implementation issues of a typical optical transmitter, which uses these techniques, are discussed. Experimental results of a laboratory long-haul WDM optical system using spectrally shaped PDM-16-QAM type modulation are presented demonstrating near Nyquist channel spacing on a trans-pacific length system with more than 44 terabits of capacity. We also present an additional application of these spectral shaping techniques, which can carefully expand the bandwidth of the transmitted channels to reduce non-linear transmission penalties. Experimental results show the advantages of these spectral broadening techniques and their ability to trade spectral efficiency for increased reach.

49.3 Tb/s Transmission Over 9100 km Using C+L EDFA and 54 Tb/s Transmission Over 9150 km Using Hybrid-Raman EDFA

We review recent high capacity ultralong haul demonstrations using amplification schemes with extended C+L optical bandwidth and optimized nonlinear performance. These demonstrations achieve 49.3 Tb/s capacity over 9100 km with the use of C+L EDFAs and 54 Tb/s capacity over 9150 km using hybridRaman EDFAs. Using the same hybrid-Raman EDFAs, a capacity of 52.2 Tb/s over 10 230 km (534 Pb/s*km) was also demonstrated. Different combinations of three 16QAM-based coded modulation schemes with spectral efficiencies SE = 4.86, 5.4/5.45, 6.14 bit/s/Hz were used in order to maximize capacity for each amplification scheme and transmission distance. We also compare the merits of optimized transmission performance of hybrid Raman-EDFA and C+L EDFA amplification schemes based on our loop experiments. At the nonlinear limit, the use of hybrid Raman-EDFA provides a modest 9.5% increase in capacity at a cost of ~2× higher electrical power.

Transmission performance of coded modulation formats in a wide range of spectral efficiencies

We experimentally study the performance of coded-modulation formats based on Nyquist-spectrally-shaped mQAM constellations with spectral efficiencies from 2.4 to 8.0 bits/s/Hz, and demonstrate that the relative performance in uncompensated links depends only on their respective OSNR sensitivity.

High-speed and transoceanic distance transmission with hybrid Raman-EDFA and coded modulation

We review recent high-capacity ultra-long haul experiments using hybrid Raman-EDFAs with optimized nonlinear performance and coded modulation with variable spectral efficiency. We discuss techniques that enabled record capacity (54Tb/s over 9,150km) and record capacity-distance product 534Pb/s*km (52.2Tb/s over 10,230km) demonstrations.

SDM for Power-Efficient Undersea Transmission

We discuss space division multiplexing as a means of increasing link capacity for power limited transmission in undersea communication. Theoretical study of erbium-doped fiber amplifiers-based space division multiplexing (SDM) transmission shows the existence of optimal values of spectral efficiency, signal-to-noise ratio, and span length that maximize power efficiency. We experimentally confirm the existence of an optimal spectral efficiency and demonstrate power efficient SDM transmission using 12-core multicore fiber. Modulation format, amplifier, and link design are discussed in connection to SDM power efficient transmission.