Horst Wernz

Measurement of the dispersion tolerance of optical duobinary with an MLSE-receiver at 10.7 Gb/s

We experimentally demonstrate a significant improvement in the dispersion tolerance of optical duobinary modulation when employing an MLSE instead of a standard receiver. We show that the improvement critically depends on the MLSE design.

Record 59-krad/s Polarization Tracking in 112-Gb/s 640-km PDM-RZ-DQPSK Transmission

We present results obtained with a fast optical polarization controller. Tracking errors were <; 0.208 rad on the Poincaré sphere during 282 hours of endless polarization scrambling at up to 60 krad/s speed. Fifty-kilorad/second polarization changes were tracked at wavelengths between 1513 nm and 1600 nm. With this subsystem we optically demultiplexed the two polarizations of a 112-Gb/s PDM-RZ-DQPSK signal transmitted over 640 km of fiber at 59 krad/s. This is the fastest polarization control reported for this or higher bitrate and direct detection.

Endless Optical Polarization Control at 56 krad/s, Over 50 Gigaradian, and Demultiplex of 112-Gb/s PDM-RZ-DQPSK Signals at 3.5 krad/s

In this paper, we present an field-programmable gate array-based automatic endless optical polarization control system, which drives a commercial LiNbO3 polarization transformer. It is capable of tracking endless polarization changes of up to 56 krad/s with mean and maximum polarization errors of 0.077 and 0.197 rad, respectively. While tracking up to 50 krad/s, the system was likewise tested over >2 weeks with maximum polarization error of 0.195 rad during which time it tracked polarization changes of 50 Gigaradian. 112-Gb/s polarization-division multiplexed return to zero differential quadrature phase-shift keying transmission with direct detection and polarization scrambling up to 3.5 krad/s is also demonstrated.

Analysis of Crosstalk in Mixed 43 Gb/s RZ-DQPSK and 10.7 Gb/s DWDM Systems at 50 GHz Channel Spacing

In DWDM field experiments over 1047 km of standard fiber and in simulations we analyze the impact of crosstalk on a 43 Gb/s RZ-DQPSK channel both by 10.7 Gb/s OOK and 43 Gb/s RZ-DQPSK neighbors at 50 GHz channel spacing.

Experimental experiences in high speed DQPSK transmission

Field and laboratory experiments show RZ-DQPSK being a suitable format for 40Gb/s long haul transmission also in mixed rate systems. Trials demonstrate transmission well beyond 1000km for non-ideal fiber spans at higher loss and PMD.

43Gb/s RZ-DQPSK Field Upgrade Trial in a 10Gb/s DWDM Ultra-Long-Haul Live Traffic System in Australia

43 Gb/s upgrade possibility of two existing DWDM links of >1100 km length between Melbourne and Sydney carrying live 10 Gb/s line traffic has been demonstrated. The trial showed a smooth 43 Gb/s introduction with >6 dB of margin and high performance stability.

Nonlinear tolerance of 112-Gb/s DP-QPSK in a live field upgrade trial over a 848km 10G DWDM link

An in-service field trial with coherently detected DP-QPSK at 112 Gb/s was performed over a Telefónica live link of 848km, testing long term stability and determining noise margin and optimum launch power of the format.

Field Trial to Upgrade an Existing 10 Gbit/s DWDM Link by 40 Gbit/s RZ-DQPSK Channels

Data rates generated in the access network by new services and customer demand on triple play influence on the transmission capacity and flexibility of the transport network. A field trial to upgrade an existing DWDM link with 10 Gbit/s RZ- and NRZ-channels by 40 Gbit/s RZ-DQPSK-channels was performed on a link consisting of legacy G.652 fibre with two ROADM and EDFA amplification only. The field link had a length of 1047 km. To obtain a high spectral efficiency of the 40 Gbit/s transport the channel spacing was reduced from 100 GHz to 50 GHz. We investigated channel crosstalk for 50 GHz and 100 GHz channel spacing, mixed types of neighbour channels, PMD and chromatic dispersion tolerance which influence on maximum transparent transmission length and signal quality of the 40 Gbit/s signal in a field experiment.

21-GHz single-band OFDM transmitter with QPSK modulated subcarriers

We present a single-band OFDM transmitter that allows the generation of signals with a bandwidth of up to 21 GHz. Transmission experiments over up to 641 km without optical dispersion compensation demonstrate the performance with coherent reception.

43 Gb/s RZ-DQPSK Transmission over a 660 km 10.7 Gb/s DWDM Link

Transmission of a 43 Gb/s RZ-DQPSK signal over an 8-span EDFA-based 10.7 Gb/s DWDM link is demonstrated experimentally. The influence of neighbouring 10.7 Gb/s NRZ channels and of the dispersion compensation is investigated.