The need to support the growing traffic demand in different communications applications motivated researchers all over the world to explore techniques able to increase the capacities of the optical fiber systems. Many methods have been proposed in order to avoid the employment of many fibers in parallel. Mode division multiplexing (MDM) is one technique, exploited only recently, able to increase the capacity with the number of the optical modes propagating in the fiber, maintaining the same amount of space of the single fiber itself. In MDM implementations the mode multiplexing/demultiplexing remains a critical issue. Photonic lanterns (PLs) are proposed to multiplex and demultiplex in a passive and all-optical way the spatial mode propagating in a few mode fiber (FMF). The combination of PLs and FMF allows to design a MDM system with increased capacity, but characterized by low complexity with respect to MDM solutions supported by electronic MIMO processing to manage the modes. Experimental characterization of different types of PLs (selective and non-selective) is preliminarly presented to better understand their technological limitations. By considering the tested PLs, we analyze the performance of a PL-based MDM system, showing the capability to increase the whole capacity also in presence of a significant inter-modal crosstalk. The exploitation of multiple subcarrier modulation (DMT) allows to maximize the transported capacity with respect to the different intermodal-crosstalk conditions. The analyzed MDM system appears interesting in case of short-reach applications, such as intra-datacenter and intra-satellite connections, where low power consumption and high compactness are mandatory.
La necessit\`a di supportare una domanda di traffico crescente in diverse applicazioni di comunicazione ha motivato i ricercatori in tutto il mondo ad esplorare tecniche che siano in grado di aumentare le capacit\`a dei sistemi in fibra ottica. Molti metodi sono stati proposti per evitare l'uso di molte fibre in parallelo. La multiplazione a divisione di modo (MDM) \`e una tecnica, sfruttata solo di recente, che \`e in grado di aumentare la capacit\`a con il numero di modi ottici che propagano in fibra, mantenendo lo stesso spazio della singola fibra. Nelle implementazioni MDM la multiplazione e demultiplazione di modo rimane un problema critico. Le lanterne fotoniche (PL) sono state proposte per multiplare e demultiplare i modi spaziali che propagano in fibre Few-mode (FMF) in una soluzione passiva e tutto-ottica. La combinazione di PL e FMF permette di progettare un sistema MDM con capacit\`a aumentata, ma caratterizzato da una bassa complessit\`a rispetto a soluzioni MDM supportate da processing elettronico MIMO per gestire i modi. Una caratterizzazione sperimentale dei diversi tipi di PL (selettivi e non selettivi) \`e presentata in fase preliminare per meglio comprendere le loro limitazioni tecnologiche. Considerando le PL testate, abbiamo analizzato la performance di un sistema MDM basato su PL, che mostra l'abilit\`a di aumentare la capacit\`a totale anche in presenza di crosstalk inter-modale. Lo sfruttamento di modulazioni a multipla sottoportante (DMT) permette di massimizzare la capacit\`a trasportata rispetto alle differenti condizioni di crosstalk intermodale. Il sistema MDM analizzato appare interessante in caso di applicazioni a corto raggio, come connessioni intra-datacenter e intra-satellitari, dove un basso consumo di potenza ed un'alta compattezza sono obbligatorie.
MDM system based on photonic lanterns exploitation
AL-CHALABI, SAAD BASIL SAAD
2016/2017
Abstract
The need to support the growing traffic demand in different communications applications motivated researchers all over the world to explore techniques able to increase the capacities of the optical fiber systems. Many methods have been proposed in order to avoid the employment of many fibers in parallel. Mode division multiplexing (MDM) is one technique, exploited only recently, able to increase the capacity with the number of the optical modes propagating in the fiber, maintaining the same amount of space of the single fiber itself. In MDM implementations the mode multiplexing/demultiplexing remains a critical issue. Photonic lanterns (PLs) are proposed to multiplex and demultiplex in a passive and all-optical way the spatial mode propagating in a few mode fiber (FMF). The combination of PLs and FMF allows to design a MDM system with increased capacity, but characterized by low complexity with respect to MDM solutions supported by electronic MIMO processing to manage the modes. Experimental characterization of different types of PLs (selective and non-selective) is preliminarly presented to better understand their technological limitations. By considering the tested PLs, we analyze the performance of a PL-based MDM system, showing the capability to increase the whole capacity also in presence of a significant inter-modal crosstalk. The exploitation of multiple subcarrier modulation (DMT) allows to maximize the transported capacity with respect to the different intermodal-crosstalk conditions. The analyzed MDM system appears interesting in case of short-reach applications, such as intra-datacenter and intra-satellite connections, where low power consumption and high compactness are mandatory.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/135974