Space-division multiplexing: the next frontier in optical communication

Abstract

Space-division multiplexing (SDM) uses multiplicity of space channels to increase capacity for optical communication. It is applicable for optical communication in both free space and guided waves. This paper focuses on SDM for fiber-optic communication using few-mode fibers or multimode fibers, in particular on the critical challenge of mode crosstalk. Multiple-input-multipleoutput (MIMO) equalization methods developed for wireless communication can be applied as an electronic method to equalize mode crosstalk. Optical approaches, including differential modal group delay management, strong mode coupling, and multicore fibers, are necessary to bring the computational complexity for MIMO mode crosstalk equalization to practical levels. Progress in passive devices, such as (de)multiplexers, and active devices, such as amplifiers and switches, which are considered straightforward challenges in comparison with mode crosstalk, are reviewed. Finally, we present the prospects for SDM in optical transmission and networking.

Ultrafast-laser-inscribed 3D integrated photonics: challenges and emerging applications

“…In both cases, the transmission capacity scales proportional to the number of single-mode cores or number of modes supported by the few-moded optical fibre, respectively. Furthermore, space-division multiplexing brings significant improvements in cost per bit as well as energy efficiency because of a reduction in the number of individual components in optical communication systems compared to individual single-mode fibres [1,139].…”

Optical Communication: Its History and Recent Progress

“…One proposed solution makes use of space-division multiplexing (SDM) to increase the capacity of fiber-optic communication networks at a reduced energy cost per transmitted bit [23][24][25][26]. The basic idea is to employ multimode fibers such that several WDM bit streams can be transmitted over different modes of the same fiber.…”

“…Similar to the case of WDM technology, the implementation of SDM requires not only new types of fibers but also many other active and passive optical components such as mode multiplexers/demultiplexers and fiber amplifiers that can amplify signals in all modes/cores simultaneously. A lot of progress has been made since 2010 in realizing such devices and many laboratory demonstrations have shown the potential of SDM for enhancing the system capacity [23][24][25][26]. .…”

Fiber propagation of vector modes

“…A key technique in achieving high-capacity optical communication is that of mode division multiplexing (MDM), which uses the spatial modes of light as information carriers [1], and has been shown promise in both free-space [2,3] and fiber [4,5]. To date there has been work on MDM with orbital angular momentum (OAM) [6], Bessel beams [7,8] and linearly polarized (LP) modes commonly used to describe fiber modes [9].…”