Impact of power allocation strategies in long-haul few-mode fiber transmission systems

Abstract

Abstract:We report for the first time on the limitations in the operational power range of few-mode fiber based transmission systems, employing 28Gbaud quadrature phase shift keying transponders, over 1,600km. It is demonstrated that if an additional mode is used on a preexisting few-mode transmission link, and allowed to optimize its performance, it will have a significant impact on the pre-existing mode. In particular, we show that for low mode coupling strengths (weak coupling regime), the newly added variable power mode does not considerably impact the fixed power existing mode, with performance penalties less than 2dB (in Q-factor). On the other hand, as mode coupling strength is increased (strong coupling regime), the individual launch power optimization significantly degrades the system performance, with penalties up to ~6dB. Our results further suggest that mutual power optimization, of both fixed power and variable power modes, reduces power allocation related penalties to less than 3dB, for any given coupling strength, for both high and low differential mode delays.

Recent progress in optical devices for mode division multiplex transmission system

“…The strongly coupled approach aims at mitigating the DMGD so that the LP modes are simultaneously detected using complex MIMO technique [92,93]. In this approach, the coupling is not viewed as issue, but the fibre requires a careful design strategy to minimise DMGD.…”

Space-division multiplexing: the next frontier in optical communication

“…MDL in general reduced the capacity of SDM systems. Theoretically, the best approach to achieve maximum capacity in the presence of MDL is to transmit more power (at higher spectral efficiency) for the superposition of modes corresponding to the eigen-vectorH † •H [195] with the largest eigenvalue. Practically, this requires that the transmitter be in command of the transfer matrix, also known as channel state information, which is not possible for long-haul transmission systems.…”

Fiber Nonlinearity Compensation: Commercial Applications and Complexity Analysis

“…5 shows a conceptual diagram for this scenario, where mixed data-rate traffic may be launched at homogenous power or heterogeneous power. Note that the choice of launch power strategy is an important system design criterion, and based on a given configuration, either self-favoring or altruistic launch power may be employed, as discussed in [57][58][59][60]. On the other hand, when higher order modulation is introduced, with delta power between upgraded and legacy traffic, intra-channel NLC gain is increased to ~3.7dB.…”