Jin-Xing Cai

20 Tbit/s Transmission Over 6860 km With Sub-Nyquist Channel Spacing

We demonstrate that channel spacing can be reduced to values smaller than the Nyquist channel spacing over transoceanic distance. Modulation memory induced by constrained transmitter bandwidth together with multisymbol detection can reduce intersymbol interference for systems with sub-Nyquist channel spacing. We transmit 198 × 100 G bandwidth constrained polarization-division-multiplexed return-to-zero quaternary phase shift keying channels with 400% spectral efficiency over 6860 km using 52 km spans of 150 μ m2 fiber and simple single-stage erbium-doped fiber amplifiers without any Raman amplification. We also show that 100 G coherent nonlinear performance scales differently with distance on uncompensated dispersion maps compared with direct detection transmission.

Transmission of 96×100G pre-filtered PDM-RZ-QPSK channels with 300% spectral efficiency over 10,608km and 400% spectral efficiency over 4,368km

We transmitted 96 × 100 G pre-filtered PDM-RZ-QPSK channels with 300% spectral efficiency over 10,608 km using 52 km spans of 150 μm2 fiber and simple single-stage EDFAs. We also achieved 400% spectral efficiency over 4,368 km using similar techniques.

RZ-DPSK field trial over 13,100 km of installed non slope-matched submarine fibers

This work presents the first field trial using the return-to-zero differential-phase-shift-keying (RZ-DPSK) modulation format. A 96/spl times/10-Gb/s RZ-DPSK field trial was conducted over a 13 100-km optical undersea path by double passing the installed 6550-km underwater link which was deployed with non-slope-matched submarine fibers. All channels performed with more than a 3-dB forward-error correction margin, including channels that accumulated over /spl plusmn/13 000ps/nm of dispersion. It is also shown that the RZ-DPSK format has similar residual dispersion and channel power tolerance for both slope-matched and non-slope-matched fibers. Furthermore, it is demonstrated that the chirped RZ-DPSK format could further improve system performance by 1-2 dB.

Transmission of 96

We demonstrated that simple pre-filtering at the transmitter to constrain the channel bandwidth together with a maximum a posteriori probability (MAP) detection algorithm can significantly improve spectral efficiency (SE). 96 × 100-Gb/s bandwidth-constrained polarization-division-multiplexing return- to-zero-QPSK channels were transmitted with 300% SE over 10 610 km using 52-km spans of 150-μ m 2 fiber and simple single-stage erbium-doped fiber amplifiers without any Raman amplification. We also achieved 400% SE over 4370 km using similar techniques.

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We present an experimental investigation of 40 Gb/s transmission technology aimed at an aggregate capacity exceeding 1 Tb/s over multithousand kilometer transmission distances. These studies have been performed using a variety of dispersion management and modulation techniques. The transmission distances investigated range from a minimum of 2000 km, which is considered a regional undersea cable distance, up to a transatlantic distance of 6200 km. Our regional distance experiments were performed using both slope-matched and conventional dispersion maps where the accumulated dispersion becomes large for the edge channels. Dispersion map studies showed that slope-matched fiber performs better than nonslope-matched fiber (NZDSF) beyond 2000 km due to its larger effective area and lower accumulated dispersion slope. The demonstration of 38/spl times/40 Gb/s over 6200 km was the first transoceanic length experiment using 40 Gb/s DWDM channels. This was achieved with a relatively simple amplifier chain that uses only C-band EDFAs. Modulation format studies showed that RZ performs better over transoceanic distance, carrier-suppressed RZ performs better with nonslope-matched fiber at a distance of 2055 km, and prefiltered carrier-suppressed RZ is more suited for higher spectral efficiency. Experimental techniques for high bit-rate experiments are presented.

100-Gb/s Bandwidth-Constrained PDM-RZ-QPSK Channels With 300% Spectral Efficiency Over 10610 km and 400% Spectral Efficiency Over 4370 km

One hundred and eighty 10 Gb/s WDM channels were transmitted over 7000 km in 43 nm of optical bandwidth with a maximum spectral efficiency of 0.4 (bits/s)/Hz. Error free performance was measured for all channels using an advanced error correcting code.

Long-haul 40 Gb/s DWDM transmission with aggregate capacities exceeding 1 Tb/s

We transmit 160 x 100 G PDM RZ 16 QAM channels with 5.2 bits/s/Hz spectral efficiency over 6,860 km. There are more than 3 billion 16 QAM symbols, i.e., 12 billion bits, processed in total. Using coded modulation and iterative decoding between a MAP decoder and an LDPC based FEC all channels are decoded with no remaining errors.

1800 Gb/s transmission of one hundred and eighty 10 Gb/s WDM channels over 7000 km using the full EDFA C-band

We present the first multi-terabit/s transoceanic length transmission demonstration using the RZ-DPSK format at a 10 Gb/s channel data rate. Error-free performance for 373-10 Gb/s RZ-DPSK channels after 11,000 km was demonstrated.

16QAM transmission with 5.2 bits/s/Hz spectral efficiency over transoceanic distance

We transmit 112×112 Gb/s pre-filtered PDM RZ-QPSK channels with 360% spectral efficiency over 9,360km with the channel spacing set to the baud rate. This results in a record spectral efficiency for transpacific distance.

A DWDM demonstration of 3.73 Tb/s over 11,000 km using 373 RZ-DPSK channels at 10 Gb/s

Two hundred and fifty six 10 Gb/s WDM channels were transmitted over 11,000 km in 80 nm of continuous optical bandwidth of hybrid Raman/EDFA for the first time. Using FEC all channels were decoded error free.