Guillaume Le Cocq

Modeling and characterization of a few-mode EDFA supporting four mode groups for mode division multiplexing

Numerical and experimental study of a Few-Mode (FM) Erbium Doped Fiber Amplifier (EDFA) suitable for mode division multiplexing (MDM) is reported. Based on numerical simulations, a Few-Mode Erbium Doped Fiber (FM-EDF) has been designed to amplify four mode groups and to equally amplify LP11 and LP21 mode groups with gains greater than 20 dB and with a differential modal gain of less than 1 dB. Experimental results confirmed the simulations with a good concordance. This modal gain equalization is obtained by tailoring the erbium spatial distribution in the fiber core with a ring-shaped profile.

Few-Mode Erbium-Doped Fiber Amplifiers: A Review

Space-division multiplexing has brought a fresh perspective to the optical fiber community over the last three years and many global players around the world have been involved with both the theoretical and the experimental questions raised by this promising approach. If this technology is to be introduced in the future optical fiber networks, this implies that most of the optical components of the transmission line, including the popular Erbium-doped fiber amplifiers that lie at the heart of fiber communications need to be reexamined. This study reviews the way the new generation of Erbium-doped fibers affects the recent findings on few-mode fibers and how they may further play a central role in the deployment of this technology.

Optimization Algorithm Applied to the Design of Few-Mode Erbium Doped Fiber Amplifier for Modal and Spectral Gain Equalization

Gradient descent optimization algorithm is applied to design few-mode Er3+-doped fibers adapted to gain equalization over modes and wavelengths, for mode division multiplexing. Theoretical study is performed for fiber designs supporting six and ten spatial modes at signal wavelength. Flat gain is obtained by optimizing Er3+ doping profile of a micro-structured core and modal composition of the pump beam.

Advanced S

Spatially and spectrally resolved imaging has become an important tool for multimode fiber characterization, both in the realms of group index dispersion measurement and modal geometry analysis. However, limited resolution in group delay space, distributed scattering and noise sometimes make the task of identifying meaningful modal interference figures difficult. In this paper, an application of multivariate statistical analysis to S2 datasets that effectively isolates mode pair interferences, both spectrally and spatially, is presented. A method to use those components to retrieve the power in each mode is also shown.

^2

We build a 5-mode amplifier with low modal crosstalk. With this amplifier we demonstrate, for the first time, an amplified transmission of 100Gbits/s signals over 80km of few mode fiber with low signal processing complexity.

Imaging: Application of Multivariate Statistical Analysis to Spatially and Spectrally Resolved Datasets

We describe a few-mode erbium-doped fiber amplifier with ring-doped erbium doping profile fiber and optimized optical setup amplifying LP01, LP11, and LP21 modes, simultaneously. Spectral and modal gain distribution is characterized as well as modal crosstalk. We study the gain evolution of every mode in several configurations, changing the input power or the number of injected modes. The gain is above 13 dB for all modes and its differential modal gain is lower than 5.7 dB across the whole C-band with a 3.5-m-long erbium-doped fiber when using a pump at 630 mW. As a proof of concept, we transmit up to five modes carrying each a PDM-QPSK signal at 32 Gbd through this amplifier.

5-Mode amplifier with low modal crosstalk for spatial mode multiplexing transmission with low signal processing complexity

Characterization of spatial mode content and dispersion properties in fiber laser systems and space-division multiplexing (SDM) applications is key to understanding fiber properties and system performance. Several techniques exist for modal characterization but often present limitations in the context in which they can be used efficiently. In this paper, we present a powerful analysis scheme that removes several of those limitations and pushes modal content analysis to a new level.

A Five-Mode Erbium-Doped Fiber Amplifier for Mode-Division Multiplexing Transmission

We report on the study of a possible first step integration of mode division multiplexed optical component for single-mode fiber networks. State-of-the-art on few-mode erbium-doped fiber amplifiers is used to integrate the amplification function in a single component, which is expected to save energy in comparison to parallelized active components. So as to limit the impact of modal cross-talk, an elliptical-core few-mode erbium-doped fiber has been used to assemble an amplifier sharing setup for different single mode fibers, using non-degenerate modes. With this simple setup, we show the level of performances that can be reached for cross-talk, gain, differential modal gain and losses and discuss the ways to improve them for a possible integration in a real network.

Advanced S2 imaging spatial mode analysis: furthering modal characterization

Optimization algorithm is applied to design Er3+-doped fibers with micro-structured core. Both Er3+ profile and modal composition of the pump beam are optimized for mode and wavelength division multiplexing gain equalization.

Amplification sharing of non-degenerate modes in an elliptical-core few-mode erbium-doped fiber

We developed a generalized field-propagating model for active optical fibers that takes into account mode beating and mode coupling through the amplifying medium. We applied the model to the particular case of a few-mode erbium doped fiber amplifier. Results from the model predict that mode coupling mediated by the amplifying medium is very low. Furthermore, we applied the model to a typical amplifier configuration. In this particular configuration, the new model predicts much lower differential modal gain than that predicted by a classical intensity model.