Patent ID: 8111962
Filing Date: 2012-02-07
Classification: G02B

Abstract:
1. An optical fiber structure in which transmission light is input through a first single-mode fiber to a second single-mode fiber, wherein the second single-mode fiber includes a core, a first cladding, and a second cladding having a lower refractive index than that of the first cladding at a wavelength of the transmission light, the core, the first cladding, and the second cladding are arranged concentrically in a sequential order from a center of the second single-mode fiber, the second single-mode fiber has a normalized frequency greater than or equal to 2.405 and less than or equal to 3.9, holes are formed in the second cladding to extend along the core, and portions of the holes corresponding to an end portion of the second single-mode fiber connected to the first single-mode fiber are filled over a length greater than or equal to 2 mm and less than or equal to 30 mm so that a corresponding portion of the second cladding is solid.