Photonic crystal fibre (PCF) having multiple cladding layers

摘要

In an optical fiber including a core region and cladding regions of not less than three layers which surround the core region in order, at least one of the cladding regions has lower mean refractive index than both adjacent regions, and at least one cladding region is provided with a plurality of sub medium regions each having a refractive index lower than a main medium constituting this cladding region. <IMAGE>