OPTICAL FIBER NONLINEAR OPTICAL FIBER OPTICAL AMPLIFIER USING IT WAVELENGTH CONVERTER AND MANUFACTURE METHOD OF OPTICAL FIBER

摘要

PURPOSE: A nonlinear optical fiber, optical amplifier and wavelength converter using the same, and method of making optical fiber are provided to sufficiently shorten a cutoff wavelength lambda c by employing a double-cladding structure. CONSTITUTION: The optical fiber is an optical waveguide mainly composed of SiO2 (silica glass). And the optical fiber comprises a core region(10) including the center axis of the optical fiber, a first cladding region(20) disposed at the outer periphery of the core region(10) and a second cladding region(30) disposed at the outer periphery of the first cladding region(20). The core region(10) has an outer diameter of 2r1, and is formed such that pure SiO2 glass is doped with a predetermined amount of GeO2 as a dopant for raising the refractive index, whereby its refractive index attains a maximum value of n1 (n1 n0, where n0 is the refractive index of pure SiO2). The core region(10) in this embodiment has a graded refractive index distribution in which the doping amount of GeO2 and refractive index are maximized in the vicinity of the center axis of the optical fiber.