ABSTRACT
A number of critical issues for dual-polarization single- and multi-band optical orthogonal-frequency division multiplexing (DP-SB/MB-OFDM) signals are analyzed in dispersion compensation fiber (DCF)-free long-haul links. For the first time, different DP crosstalk removal techniques are compared, the maximum transmission-reach is investigated, and the impact of subcarrier number and high-level modulation formats are explored thoroughly. It is shown, for a bit-error-rate (BER) of 10(-3), 2000 km of quaternary phase-shift keying (QPSK) DP-MB-OFDM transmission is feasible. At high launched optical powers (LOP), maximum-likelihood decoding can extend the LOP of 40 Gb/s QPSK DP-SB-OFDM at 2000 km by 1.5 dB compared to zero-forcing. For a 100 Gb/s DP-MB-OFDM system, a high number of subcarriers contribute to improved BER but at the cost of digital signal processing computational complexity, whilst by adapting the cyclic prefix length the BER can be improved for a low number of subcarriers. In addition, when 16-quadrature amplitude modulation (16QAM) is employed the digital-to-analogue/analogue-to-digital converter (DAC/ADC) bandwidth is relaxed with a degraded BER; while the 'circular' 8QAM is slightly superior to its 'rectangular' form. Finally, the transmission of wavelength-division multiplexing DP-MB-OFDM and single-carrier DP-QPSK is experimentally compared for up to 500 Gb/s showing great potential and similar performance at 1000 km DCF-free G.652 line.
ABSTRACT
The transmission performance of coherent dual-polarization multi-band OFDM (DP-MB-OFDM) and QPSK (DP-QPSK) are experimentally compared for 100 Gb/s long-haul transport over legacy infrastructure combining G.652 fiber and 10 Gb/s WDM system. It is shown that DP-MB-OFDM and DP-QPSK have nearly the same performance at 100 Gb/s after transmission over a 10 × 100-km fiber line. Furthermore, the origin of performance degradations and limitations of the DP-MB-OFDM is explored numerically, as well as the impact of transmission distance and sub-band spacing.
Subject(s)
Computer Communication Networks/instrumentation , Fiber Optic Technology/instrumentation , Refractometry/instrumentation , Signal Processing, Computer-Assisted/instrumentation , Telecommunications/instrumentation , Equipment Design , Equipment Failure Analysis , MicrowavesABSTRACT
In this work we present extensive comparisons between numerical modelling and experimental measurements of the transmission performance of either CSRZ-ASK or CSRZ-DPSK modulation formats for 40-Gb/s WDM ULH systems on UltraWave(TM) fiber spans with all-Raman amplification. We numerically optimised the amplification and the signal format parameters for both CSRZ-DPSK and CSRZ-ASK formats. Numerical and experimental results show that, in a properly optimized transmission link, the DPSK format permits to double the transmission distance (for a given BER level) with respect to the ASK format, while keeping a substantial OSNR margin (on ASK modulation) after the propagation in the fiber line. Our comparison between numerical and experimental results permits to identify what is the most suitable BER estimator in assessing the transmission performance when using the DPSK format.
ABSTRACT
Nonlinearity management is explored as a complete tool to obtain maximum transmission reach in a WDM fiber transmission system, making it possible to optimize multiple system parameters, including optimal dispersion pre-compensation, with fast simulations based on the continuous-wave approximation.
ABSTRACT
The effect of combined use of in-line filtering and synchronous intensity modulation on interactions is investigated both analytically and numerically in a 40-Gbit/s dispersion-managed link. Numerical results confirm analytical predictions and show that interactions are efficiently suppressed.
ABSTRACT
We demonstrate numerically that local conversion of dispersion-managed return-to-zero pulses into nonlinear Schrödinger solitons fully restores optical filtering control for energy stabilization, thus permitting the association of optical regeneration with dispersion-managed propagation. Experimental validation is achieved by means of 40-Gbit/s regenerated dispersion-managed loop transmission over 10,000 km.
ABSTRACT
Dispersion-managed solitons with in-line all-optical regeneration are shown to be subject to amplitude and timing-jitter instabilities. We identify and discuss the different natures of these instabilities by means of a linear stability analysis, which is in good agreement with the full numerical solutions of the governing equations. Stable pulse propagation can be achieved through appropriate choices of dispersion map and pulse energy.
ABSTRACT
The feasibility of 1-Tbit/s transoceanic systems based on in-line optical regeneration of 40-Gbit/s channels is numerically investigated. The roles of fiber dispersion, fiber mode area, and channel and regenerator spacings are analyzed, and the corresponding operating ranges for error-free transmission are determined. The results represent a first step in designing multi-terabit-per-second global transmission systems based on realistic components and parameters.
