摘要： Current forecasts indicate that the fastest growing IP-traf?c is in metro and data center interconnect (DCI) [1]. The exploitation of the entire low-loss spectrum of single-mode ?bers (SMF) (from 1260 nm up to 1620 nm) was proposed to avoid the predictable capacity crunch and the eventual need for a new ?bre infrastructure roll-out. First analytic result considering multi-band (MB) transmission (from O- to L-band) hint an achievable traf?c load exceeding 200 Tb/s for a 500 km link in a single SMF [2]. The maximum transmittable capacity over ITU-T G.652D SMF, which is the mainly deployed ?ber type [3], is evaluated in this work. Three different ?ber span lengths are considered: 40 km, 60 km and 80 km. A high level overview of the MB setup is depicted in Fig. 1 (left). The system is composed of a MB transmission bench composed of {L, C, S, E, O}-band transmitters. 50 GHz spaced polarization multiplexed (PM)-MQAM signals with root raised cosine shaping (roll-off = 0.15) and a symbol rate of 32 Gbaud are multiplexed and launched into the ?ber link. A 2 nm guard-band between adjacent bands is assumed. At the receiver side, the bands are de-multiplexed, ampli?ed and then demodulated. We assume lumped ampli?ers: Praseodymium doped ?bre ampli?er(DFA) in O-band [4], Bismuth DFA in E-band [5], Thulium DFA in S-band [6] and Erbium DFA in C- and L-bands. A noise ?gure of 6, 5.5, 7, 6 and 7 dB are assumed for {L, C, S, E, O}-band ampli?ers, respectively. The wavelength ranges and number of channels in each band are reported in Table 1. The local-optimization global-optimization (LOGO) approach [7] is employed to optimize the launched power. The overall signal-to-noise-ratio (SNR) is estimated considering the impact of non-linear interference (NLI) which is evaluated using the generalized Gaussian noise (GGN) model [8]. The GGN model takes into account the frequency dependence of the ?ber loss, the chromatic dispersion and the stimulated Raman scattering (SRS). Finally, the achievable capacity assuming a ?exible transceiver capable to completely exploit the available SNR is computed.