Unrepeatered field transmission of 2 Tbit/s multi-banded coherent WDM over 124 km of installed SMF

Abstract

In this paper we report field transmission of a 2 Tbit/s multi-banded Coherent WDM signal over BT Ireland's installed SMF, using EDFA amplification only, with mixed Ethernet (with FEC) and PRBS payloads. To the best of our knowledge, the results obtained represent the highest total capacity transmitted over installed SMF with orthogonal subcarriers. BERs below 10(-5) and no frame-loss were recorded for all 49 subcarriers. Extended BER measurements over several hours showed fluctuations that can be attributed to PMD and to dynamic effects associated with clock instabilities.

All-optical OFDM and distributed Raman amplification: Challenges to enable high capacities and extend reach

“…This occurs due to an increase in nonlinearities as the FW pumps increase both the overall launch power to the fibre and the effective length. We believe that the balance between signal launch powers and DRA gain in this experiment was close to the optimum configuration for a 124 km span for a first order DRA, and the results were compared to an optimised EDFA only system (as in [ 16 ]), as shown in Figure 2(c). Again, it clearly shows an average improvement of 1.2dB in Q-factor, well above the FEC thresholds.…”

Impact of Raman Amplification on a 2-Tb/s Coherent WDM System

“…Although Raman amplification adds noise (amplified spontaneous emission (ASE) and DRB) [10]) by transforming an optical fiber into a DRA, at a fixed BER it allows lower fiber launch powers and increases the minimum signal power in the fiber. The EDFA following the DRA has also a higher input power, and thus causes a smaller OSNR degradation when compared to the EDFA-only system [3]. Optimization of a DRA system is complex because the distribution of the gain along the transmission fiber reduces the total ASE and improves the OSNR but simultaneously increases the signal distortions that result from Kerr and other nonlinearities.…”

“…An analytical model is introduced in order to identify high Q-factor operating areas. For such long unrepeatered transmission reaches using legacy installed SMF, the DRA is beneficial, with 1.2dB Q-factor enhancement compared to lumped amplification [3]. FIGURE Fig.1 shows the system configuration.…”

“…FIGURE Fig.1 shows the system configuration. The transmitter and receiver were explained in [3]; seven seed lasers spaced at 385.52GHz passed through two cascaded Mach-Zehnder modulators (MZM), generating seven CoWDM bands each containing seven orthogonal subcarriers spaced at 42.84GHz. After impressing non-return-to-zero on-off keying (NRZ-OOK) encoding with 2 31 -1 PRBS data electrically decorrelated between adjacent subcarriers, the transmitted spectrum had a total power of 8.7dBm (P TX ) over a 2.8THz bandwidth and transported a total of 2.1Tbit/s (Fig.2).…”

Potencializando a modulação adaptativa com roteamento em múltiplos saltos em redes ópticas elásticas

“…Dentre as tecnologias que permitem a flexibilidade nas redes ópticas pode-se destacar a CoWDM (Coherent Wavelehgth-division Multiplexing) [7], a CO-OFDM (Coherent Orthogonal frequency-division multiplexing) [8], a N-WDM (Nyquist-WDM ) [6] e a OAWG (Optical Arbitrary Waveform Generation) [9]. Estas tecnologias permitem a formação de subportadoras ópticas de baixa velocidade que, combinadas ortogonalmente, podem gerar canais de transmissão de tamanho flexível [6].…”