Abstract
Multi-core optical fi bers are eagerly developed recently, because they are one of strong candidates to overcome transmission capacity limit of existing optical fi bers. Number of cores and inter-core crosstalk are often highlighted in multi-core optical fiber development, because they are unique parameters of multi-core optical fibers. But, transmission loss and nonlinearity of each core are also important parameters especially for multi-core optical fi bers for long-haul and large capacity transmission systems. In this paper, following brief description of issues and measures to realize a low loss low nonlinearity multi-core optical fiber, an example of design and characteristics of a fabricated multi-core fiber is described. Impacts and future challenges of low loss low nonlinearity multi-core optical fi bers are also mentioned.
