Single mode optical fibre coupled to spacer element and graded index fibre

摘要

There are provided an optical fiber having a light focusing function and capable of setting the distance WD to the beam waist position and the beam waist diameter omega independently, and a method of manufacturing the optical fiber efficiently and at high accuracy. An end surface of a single mode optical fiber (11) is connected to one end surface of a very short piece of spacer (13) constituted of an optical fiber the diameter of which is identical to that of the single mode optical fiber and the refractive index of which is uniform. The other end surface of the spacer is connected to one end surface of a very short piece of graded index optical fiber (12) the diameter of which is identical to that of the single mode optical fiber and the refractive index of which varies continuously in the direction of its diameter. The lengths of the spacer and/or the GI fiber can be adjusted to set the beam waist distance WD and the beam waist diameter omega to a proper value suitable for an optical device to be optically coupled to the optical fiber. <IMAGE>