Patent ID: 6788865
Filing Date: 2004-09-07
Classification: G02B

Abstract:
A polarization maintaining optical fiber, comprising:a core; and a photonic crystal structure cladding provided in a surrounding of the core and having a diffraction grating with a lattice interval &Lgr; for realizing confinement of light within the core, the photonic crystal structure cladding being divided into four divided portions along a circumferential direction, all lattice holes in a first pair of divided portions that are facing each other along one direction having a larger lattice hole diameter d2 than a smaller lattice hole diameter d1 of all lattice holes in a second pair of divided portions that are facing each other along another direction orthogonal to the one direction, and in a graph in which a vertical axis represents d1/&Lgr; and a horizontal axis represents d2/&Lgr;, a ratio of the larger lattice hole diameter d2 and the smaller lattice hole diameter d1 takes a value within a region enclosed by four straight lines given by four equations: d1/&Lgr;=d2/&Lgr;d1/&Lgr;=0.2(d2/&Lgr;) d1/&Lgr;=d2/&Lgr;âˆ’0.20 d2/&Lgr;=1.0 as a condition for realizing a single peak in a light intensity distribution in a vicinity of the core.