Cornelius Fürst

10.7 Gb/s electronic predistortion transmitter using commercial FPGAs and D/A converters implementing real-time DSP for chromatic dispersion and SPM compensation

We present an experimental demonstration of simultaneous chromatic dispersion and self-phase modulation compensation at 10.7 Gb/s using real-time electronic digital signal processing. This was achieved using a pre-distorting transmitter based on commercially available field programmable gate arrays and 21.4 GS/s, 6-bit resolution digital-to-analog converters. The digital signal processing employed look-up tables stored in RAM. This resulted in the achievement of a BER of 10(-6) at an OSNR of 16 dB after transmission over a 450 km link of uncompensated standard single mode fiber with + 4 dBm launch power.

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.

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.

Group-Delay Ripple Induced Performance Degradation in Optical DQPSK Transmission

An analytical model for the group-delay ripple induced OSNR penalty in DQPSK transmission is presented. Applied to 43 Gb/s RZ-DQPSK modulation, the model shows excellent agreement with simulations.

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.

Spectral Power Fluctuations in DWDM Networks Caused by Spectral-Hole Burning and Stimulated Raman Scattering

Publisher Summary In the 1990s, spectral hole burning (SHB) in the gain spectrum of erbium-doped fiber amplifier (EDFA) was identified as a small higher order effect with magnitude of only a fraction of a dB. Likewise, the manifestation of stimulated Raman scattering (SRS) of dense wavelength division multiplexing (DWDM) channels in the transmission fiber was estimated to cause a small power transfer from short wavelength channels to the longer ones, both at the bit level and on average power basis. Even these small effects can cause significant impairment of channels in the modern wavelength division multiplexing networks, which consist of 100 or more channels covering most of the EDFA gain spectrum and transmission reach requiring concatenation of tens to hundreds of amplifiers, particularly when the channel loading in the network is changed. It therefore becomes an imperative for the system designers to quantify the system impact and then develop strategies to mitigate or manage the adverse impact of these effects. This chapter provides the physics of these effects. It also provides an assessment of the system impact of SHB and SRS through experimental investigation of gain-controlled amplifiers in a circulating loop. It describes the impact of these effects based on treating the amplifier as a black box.

Techno-Economic Analysis of Dispersion-Tolerant Transmission Techniques for 10Gb/s DWDM Systems

We analyse the prospects of dispersion-tolerant transmission techniques such as electronic distortion compensation and optical duobinary modulation. Our investigation of both technical and economical aspects shows that these techniques are predominantly beneficial for Metro DWDM transmission.

Raman plus EDFA vs. Raman only amplification in terrestrial long haul WDM transmission

Implications of using distributed Raman amplification only instead of distributed Raman amplification combined with EDFAs are analyzed from a terrestrial long haul WDM system design perspective. Results suggest that employing EDFAs in combination with Raman offers more flexibility and better system performance.