Method of making fiber coupler having integral precision connection wells

An optical fiber coupler that is adapted to be connected to a plurality of system optical fibers of predetermined diameter, said coupler comprising

• an elongated glass body having a solid midregion and first and second opposite end portions which respectively extend from said midregion to the first and second ends of said body.
• first and second longitudinal apertures respectively extending from said first and second ends of said body to said solid midregion, said longitudinal apertures having a cross-sectional shape that is a composite of a plurality of contiguous cylindrical apertures, and
• at least two glass optical fibers, each having a core and cladding, each of said fibers extending through said midregion of said body and terminating in a respective one of said apertures between said midregion and the first and second ends of said body, said midregion of said body being in intimate contact with said fibers,
• the central portion of said midregion being of smaller diameter than the remainer of said midregion, the cores of said fibers being more closely spaced in said central portion than in the remaining portions of said midregion, the sections of said apertures between the ends of said fibers and the first and second ends of said body forming wells into which said systems optical fibers can be inserted for connection to said coupler.