G. Mohs

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.

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

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.

200 Gb/s and Dual Wavelength 400 Gb/s Transmission over Transpacific Distance at 6.0 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 digital back propagation (DBP). 53 × 400 Gb/s channels are also transmitted over 9200 km detecting two 200 Gb/s wavelengths simultaneously using a wideband receiver. DBP benefit versus channel pre-emphasis, average launch power per channel, and transmission distance are experimentally investigated. We find the DBP benefit scales monotonically with channel power and transmission distance. Measurement results match well with theory.

Experimental comparison of the RZ-DPSK and NRZ-DPSK modulation formats

The RZ-DPSK and NRZ-DPSK modulation formats were experimentally compared using installed undersea fiber links. Our results show a 1-1.5 dB RZ benefit with optimized RZ modulation depth for both 25-GHz and 33-GHz spaced channels.

30.4 Tb/s transmission over transpacific distance using 200 Gb/s and dual wavelength 400 Gb/s 16QAM at 6.0 b/s/Hz spectral efficiency

Using single-stage C-band EDFAs equalized to 41 nm, we transmit 152 x 200 Gb/s PDM 16QAM channels with 6.0 b/s/Hz spectral efficiency over 9,748 km enabled by Nyquist spectral shaping and digital back propagation. 76 x 400 Gb/s channels are also transmitted over 8,665 km detecting two 200 Gb/s channels simultaneously using a single wideband receiver. Digital back propagation benefit versus channel pre-emphasis, transmission distance and wavelength are experimentally investigated.

ISI compensation up to Nyquist channel spacing for strongly filtered PDM RZ-QPSK using multi-tap CMA

We experimentally demonstrate inter-symbol interference (ISI) mitigation using a multi-tap constant modulus algorithm (CMA) for strongly filtered PDM RZ-QPSK and find it to be effective up to Nyquist channel spacing after transpacific transmission distances.

Power-Efficient 100 Gb/s Transmission Over Transoceanic System

The capacity of optical communication systems can be continuously scaled by utilizing spatial division multiplexing (SDM) technology. However, this scaling has significant impact on the required optical and electrical power as the number of EDFAs increase. This constraint is crucial in long-haul undersea optical systems where electrical power for the entire system is fed from the landing points. Successful implementation of SDM in undersea systems will require both signal modulation and amplification technologies with high power efficiency. In this work, we use 8-D coded modulation and simple EDFA design to demonstrate 100 Gb/s transmission over 9750 km with record high power efficiency as defined by the ratio of capacity-distance product to the total amplifier output power.

Power-efficient 100 Gb/s transmission over transoceanic distance using 8-dimensional coded modulation

We demonstrate 100Gb/s 8D coded modulation transmission over 9,750 km with record high power efficiency as defined by the ratio of capacity-distance product to the total amplifier output power.

Impact of fiber aging and cable repair in an installed 28-nm transatlantic 96 x 10 Gb/s DWDM system

Using the 28-nm bandwidth, transatlantic segment of the Tyco Global Networkreg, we present the first report of the impact of fiber aging and cable repairs on gain shape and performance of an installed transoceanic DWDM system

Massive Terminal Dispersion Compensation Enabling Nondispersion-Managed Submarine Links With First Generation Coherent Transponders

We numerically and experimentally investigate the limits of terminal-based optical dispersion compensation for nondispersion-managed systems, using coherent transmission technology. The resulting residual dispersion is ~50 000 ps/nm, which is within the digital signal processing compensation range of first generation coherent transponders.