Novel Optical Fibers for High-Capacity Transmission System

The rapid growth of multi-media and data rich applications has driven the bandwidth demand for long-haul fiberoptic links at unprecedented rates. At the same time, growing capacity demands also imposes challenges on bandwidth and interconnects in data centers. Optical fibers are continuing improving their performance to meet the bandwidth demand in both long haul and short reach applications. While continuing improvements in conventional fiber optic technologies will increase the system capacity further in a short term, recent studies show that the transmission capacity over single-mode optical fibers is rapidly approaching its fundamental Shannon limit. To overcome this limit, new technologies using space division multiplexing are needed to provide a solution to the future capacity growth. In this paper, we discuss novel optical fibers for increasing capacity for transmission systems. For conventional fibers for long haul transmission, because transmission impairments such as chromatic dispersion, polarization-mode dispersion can be perfectly compensated for by digital signal processing, the only fiber parameters that can be optimized further are fiber attenuation and effective area. We will discuss system figure of merit for the two parameters and present recent results on ultra-low loss and large effective area fibers. For short reach applications, we will review the current efforts in improving multimode fiber bandwidth and discuss new trends in multimode fibers to meet future bandwidth demand. For next generation fibers, we will focus on multicore and few mode fibers for space division multiplexing, which has the potential to increase the capacity by an order of magnitude. We will present fiber design considerations and review recent progress on multicore and few mode fibers. Finally, we will discuss major challenges in space division multiplexing applications using multicore and few mode fibers.