Randomly-Coupled Multi-Core Fiber Technology

Abstract

| Randomly-coupled multi-core fiber (MCF) technology has come to attract lots of attention because of its strong applicability to long-haul transmission systems. Compared with weakly-coupled MCFs with independent cores, it can simultaneously realize higher spatial channel density and ultralow transmission loss using existing ultralow-loss single-mode fiber (SMF) core designs. The strong mode coupling characteristics of randomly-coupled MCFs can provide favorable optical properties, such as suppressed accumulation of modal dispersion (MD), mode-dependent loss (MDL), and nonlinear impairments. This article gives an overview of randomly-coupled MCF technology advancements. First, we describe the classification and design of randomly-coupled MCFs and explain what the randomly-coupled MCFs are and how they are designed. State-of-the-art randomly-coupled MCFs can accommodate four, seven, or 12 cores in a standard 125-µm cladding while achieving ultralow transmission loss and/or small MD, which are very promising for long-haul transmission media. Next, we present the methods to characterize the optical properties of randomly-coupled MCFs and the difference compared to conventional SMF measurements. We also show the low-loss low-MDL connectivity of Manuscript

The Role of Parallelism in the Evolution of Optical Fiber Communication Systems

“…This section briefly introduces the main concepts of SDM integration that have been proposed and discusses various tradeoffs. Further details are provided in other papers contained within this Special Issue, including [60], [67], [143], [144], [145], and [146].…”

“…A CCF is typically made from a few (e.g., 4 or 7; see Fig. 20) homogeneous single-mode cores that are located just at the right distance to each other to enable strong random coupling [144]. Such a fiber supports as many spatial supermodes as it has cores.…”

Maximizing the Capacity of Graded-Index Multimode Fibers in the Linear Regime

“…pace-division multiplexing (SDM) has emerged as a solution to overcome the capacity limit of single-mode fibers (SMFs) [1]. Among the possible SDM approaches, multimode fibers (MMFs) [2][3][4][5] offer the highest spatial information density followed by coupled-core multi-core fibers (MCFs) [6][7][8][9]. Spatial density plays a critical role in maximizing opportunities for opto-electronic integration gains, and transceiver-specific integration is key to the overall value proposition of SDM.…”

“…For short-reach systems at 850 nm, new types of multimode fiber increasing bandwidth several-fold have been demonstrated: a multicore multimode fiber formed from a large number of single mode cores [3] or a larger core graded-index multimode fibers [21]. For highcapacity SDM systems at ~1.55 m, there has been significant progress on coupled-core MCFs with near-zero modal dispersion [8,9,22] up to 19 cores and on rescaled standard graded-index-core MMFs [23,24] up to 55 spatial modes. Here, we extend the latter approach to a much larger number of modes (up to 1000 spatial modestwice as many polarization modes) by scaling the core-cladding contrast and the core radius within a 125 m cladding.…”

Novel Multicore Optical Fibers for Signal Distribution and Processing

“…Each subtype has specific propagation characteristics (differential group delay, mode-dependent loss, etc. ), which are related to the coupling strength [20]. While in a strongly-coupled MCF the propagation in spatial modes (or supermodes) leads to large differential group delay (DGD), in randomly-coupled MCF the random coupling between them reduces the delay spread which in turn diminishes DSP complexity.…”