Photonic crystals are known already, in some forms, for a longer time, but they become recently very popular and interesting for theoretical, numerical, experimental and application oriented research. The reasons for that are their very interesting properties exceeding characteristics and implementations limits of the traditional optical elements. Moreover in some cases they shift paradigms of optics. One of the very interesting examples of photonic crystals, intensively studied and investigated since 1990s, are photonic crystal fibers. In a brief way, the classification, few modeling approaches, unique properties, fabrication techniques, chances and threats for the potential applications are presented.