A cylindrical sleeve connector for mounting ferrules retaining optical fibers therein is formed with a plurality of perforations arranged in a given pattern so as to be elastically deformable within in a specified elastic region. The sleeve connector is produced, using electroforming process, on a cylindrical electroforming mandrel comprising a conductive rod with external surface texture that is equivalent to required internal surface texture of the sleeve connector and a non-conductive layer formed on the conductive rod so as to provide non-conductive segments identical in configuration with the perforations and arranged in conformity with the given pattern of perforations of the cylindrical sleeve connector.

An optical member (for example, optical fiber) is dipped in a coating solution having a film forming material dissolved therein to form an antireflection film on the end surface of the optical member. When the optical member is pulled up from the coating solution, the angle formed by the level of the coating solution and the end surface of the optical member, or the pulling speed is varied to adjust the film thickness or reflectance of the antireflection film to be formed on the end surface of the optical member. The film forming material is a fluorine-containing compound. The antireflection film is formed by dipping. The film thickness of the antireflection film is uneven.

An alignment procedure aligns the components of an arrayed optical fiber collimator and reduces losses associated with the collimator. Initially, an optical fiber array block including a plurality of individual optical fibers is received and retained. Next, a microlens array substrate including a plurality of microlenses integrated along a microlens surface and a substrate surface opposite the microlens surface is received and retained. Then, at least a portion of a first light receiver that is positioned to receive a light beam from at least one of the integrated microlenses is received and retained. Next, at least one light beam is provided from the light source to at least one of the plurality of individual optical fibers. Then, the position of at least one of the microlens array substrate and the optical fiber array block is adjusted in relation to each other to maximize the optical power of the light beam received by the first light receiver.

Electroforming is performed in an electroforming bath with a cathode of a metal wire member immersed in an electroforming solution to electrodeposit nickel around the aluminum alloy wire member. The aluminum alloy wire member is removed by dissolution with an alkaline solution from an obtained nickel electroformed product. Accordingly, a nickel cylinder is obtained, which has a through-hole formed corresponding to the wire member. The cylinder is cut into those having a predetermined length. The outer circumference is subjected to cutting based on the through-hole to obtain a ferrule. The inner diameter accuracy of the through-hole of the ferrule is determined by the outer diameter accuracy of the wire member.

A coupler adapter has a base and at least one alignment feature disposed upon the base. The at least one alignment feature is constructed for aligning a multi-fiber bundle to an opto-electronic module to permit transmission of optical signals between the multi-fiber bundle and optical devices within the opto-electronic module when the opto-electronic module is larger in span than a spacing of alignment elements used in a commercial connector that holds the multi-fiber bundle.