Broad bandwidth, single mode fiber optic coupler and method of manufacture

摘要

The present invention provides for a fiber optic coupler of first and second optic fibers formed by a length of the two fibers. The first optic fiber along the length has a different core diameter than that of the second optic fiber. At the both ends of the length the first and second optic fibers are twisted about each other with a central portion in which said first and second optic fibers are fused substantially parallel to each other. The resulting coupler is such that an input light signal is split into output light signals in a predetermined power ratio on the two optic fibers with the coupled power ratio relatively insensitive for a predetermined range of signal wavelengths.