EDFA Design and Analysis for WDM Optical Systems Based on Modal Multiplexing

• Main Authors: Adolfo Fernandes Herbster, Murilo Araújo Romero
• Format: Article
• Language: English
• Published: Sociedade Brasileira de Microondas e Optoeletrônica; Sociedade Brasileira de Eletromagnetismo
• Series: Journal of Microwaves, Optoelectronics and Electromagnetic Applications
• Subjects: Erbium doped fiber amplifier; few-mode fiber amplifiers; genetic algorithm; spatial division multiplexing
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S2179-10742017000100194&lng=en&tlng=en

Abstract Modal multiplexing (MDM) is a core technology to allow a capacity increase in modern optical systems. However, in MDM links, the amplified WDM signal suffers not only from lack of spectral gain equalization but also from unequal modal gain. The proper design of the MDM-EDFA is crucial to provide modal gain equalization and to overcome those impairments, thereby ensuring long haul transmission. In this paper, our methodology of project EDFA design for MDM-WDM systems is presented. The technique is based on a figure of merit arising from the rate and propagation equations which describe the EDFA behavior. This figure of merit is then used for the definition of the objective functions employed in the optimization step, which is based on the non-dominated sorting genetic algorithm NSGA-II. Finally, the method is applied to demonstrate gain equalization through the simulation of a WDM optical system composed of two group modes (LP01,s and LP11,s) with up to 16 channels in each mode. It is demonstrated that, for a MDM-WDM system with optimized EDFAs, the differential spectral gain is the main cause of non-equalization of the amplified signal.