Optical fiber with light-focusing function, and mfg. method thereof

Abstract

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 is connected to one end surface of a very short piece of spacer 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 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.

Description

technical field [0001] The present invention relates to an optical fiber with a light concentrating function added to the end of an optical fiber connected to an optical device and a manufacturing method thereof, in particular to an optical fiber capable of coupling with a specific optical device with a minimum light loss and its ability to be coupled with a high Efficient and high-precision manufacturing methods for fabricating optical fibers. Background technique [0002] The idea of ​​adding a light concentrating function to the end of an optical fiber connected to a light source, a light receiver, an optical modulator, an optical switch, and other optical devices has been suggested in the past, for example, it is disclosed in JP-A-3-189607 A scheme in which a graded-index optical fiber (hereinafter referred to as GI) in which the refractive index of the core portion changes continuously in the radial direction is connected to one end of a single-...

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Problems solved by technology

[0007] Therefore, even if the length of the GI optical fiber 12 is changed according to the type and size of the optical device coupled with the optical fiber, and the distance WD at the beam waist position is set to a predetermined value, the beam waist diameter and the optical beam waist diameter, which are changed in conjunction with each other, often occur. In the case where the device is not suitable, there is a difficulty that good coupling between the fiber and the optical device cannot be obtained by only adjusting the beam waist position by making the length of the GI fiber 12 variable.

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