Recent progress on photonic crystal fibers (PCFs) is reviewed aiming at their application to high performance optical communications sytems. The optical properties, for example dispersion characteristics, can be set by selecting the appropriate combination of air hole diameter and air hole pitch. A noteworthy characteristic of PCFs is their strong birefringence, which suggests optical components with better polarization maintaining characteristics.
This paper describes the characteristics of dispersion controlled PCFs and polarization maintaining PCFs. It describes theoretical analyses and experimental results of fabricated PCFs that have short wavelength zero dispersion at 810 nm, polarization maintaining capability with birefringence of 1 × 10−3, polarization maintaining dispersion flattened functions, and absolute single polarization state support with polarization dependent loss of 1 dB/m at 1550 nm. A supercontinuum generation experiment with PM-PCF in the 1550 nm region is shown with symmetrical spectral broadening to over 40 nm. The potential of PCFs will be discussed with reference to the next generation optical communications systems.