Optical fiber coupler and process and device for producing the same

Abstract

A conventional optical fiber coupler requires a preprocessing process or different optical fibers having strictly uniform characteristics. The inventive optical fiber coupler is a 1x2 wide band optical fiber coupler for branching or coupling propagating lights between an optical fiber (1a) and an optical fiber (1b). Both optical fibers (1a, 1b) are identical single-mode optical fibers available on the market as a standard type. An optical coupling part (21) of the optical fiber coupler is formed by fusing and elongating the optical fibers (1a, 1b) with a part of the optical fiber (1b) kept wound around the optical fiber (1a). Winding amount of the optical fiber (1b) with respect to the optical fiber (1a) is adjusted such that the difference in length between both optical fibers (1a, 1b) at the optical coupling part (21) is equal to the minimum possible length required for substantially equalizing the degrees of coupling of propagating lights at the optical fibers (1a, 1b).

Description

technical field [0001] The present invention relates to an optical fiber coupler used for branching, coupling, multiplexing and demultiplexing of optical signals, etc. in an optical communication system or an optical sensing system, etc. (fiber optic splitter). Background technique [0002] In an optical communication system, there is a wavelength multiplex communication method in which information is transmitted and received using light of a plurality of wavelengths in order to perform large-capacity communication. In the optical communication system of the wavelength multiplex communication mode, the optical fiber coupler used for optical signal monitoring, distribution, etc., multiple optical signals of each wavelength are equally branched, that is, the branching ratio and coupling ratio of each wavelength of light ( Hereinafter referred to as the degree of optical coupling) does not change due to wavelength differences, and is an important factor in system construction....

AI Technical Summary

Problems solved by technology

When the optical coupling part has a different transmission constant, the optical coupling is incomplete coupling, and the maximum coupling degree is less than 100%.

The method of using N+1 fibers as a 1×N fiber coupler, as described above, increases the wavelength dependence of the additional loss in principle

In addition, since the branching ratio is limited to equal branching, it is not possible to manufacture unequal branching fiber couplers, etc.

Furthermore, as described in the broadbandization method of Patent Document 7, in the method of introducing an asymmetric taper into a 1×N fiber coupler, the taper must be longer than actually required. In addition to somewhat increasing the overall length of the fiber coupler, Its disadvantage is the controllability of the asymmetric taper shape, which is the main reason for reducing the yield.

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