Nonlinear impairment scaling with the number of mode groups in mode-multiplexed transmission over a 50 µm multimode fiber.

Marius Brehler,Peter M Krummrich

doi:10.1364/oe.26.016393

Abstract

We numerically investigate the impact of nonlinear effects in mode-multiplexed transmission over a 50 µm graded-index multimode fiber. Such a fiber supports 36 spatial modes, well suited for a mode-multiplexed transmission. The number of mode groups used for transmission is subsequently increased to identify the nonlinear penalty occurring due to the Kerr-effect-based nonlinear interaction between the spatial modes. It is shown that the nonlinear penalty scales less than proportional with the number of modes and hence, is no obstacle for using such a fiber for a mode-multiplexed transmission. Consequently, we clarify the potential to upgrade the transmission capacity over time with such a fiber.

Highlights

The continuous growth of traffic demand in long-haul optical transmission systems leads to capacity demands which cannot be satisfied by single-mode fibers [1]
We numerically investigate the impact of nonlinear effects in mode-multiplexed transmission over a 50 μm graded-index multimode fiber
Low complexity multiple-input multiple-output (MIMO) equalizer is needed at the receiver, leading to the requirement of small differential mode group delays (DMGD) [1]

Summary

Introduction

The continuous growth of traffic demand in long-haul optical transmission systems leads to capacity demands which cannot be satisfied by single-mode fibers [1]. To make full use of the capacity of 50 μm MMFs in long-haul transmissions, further mode groups need to be utilized. We investigate in which way the Kerr-nonlinearity scales with the number of utilized mode groups in our contribution. The scaling of nonlinear impairment with the number of modes was investigated numerically for up to 15 spatial modes in [11] for a single wavelength channel. Combining modedivision multiplexing (MDM) with wavelength-division multiplexing (WDM) was numerically investigated for 15 spatial modes in [12] We extend both and examine the nonlinear impairment, scaling with the number of used mode groups in a WDM-MDM transmission over a 50 μm MMF, by numerical simulations. To the authors’ best knowledge, this is the first investigation of the scaling of nonlinear impairment for such a high number of modes

Signal propagation and transmission set-up

Simulation results and discussion

Conclusions