A method for connecting optical signals carried by optical fibers between an optical encoder readhead and an optical signal processing IC having a plurality of photodetector portions arranged in a photodetector configuration. The optical signal processing IC is fixed to a substrate at a first position and orientation. Then, a reference-surface block including at least one reference surface is fixed to the substrate in a second orientation and position based on the first position and orientation. A fiber-optic end piece is provided, which has at least one corresponding-reference surface and a plurality of optical fiber locating features that are arranged relative to the corresponding-reference surface. A plurality of the optical fibers are fixed to the plurality of optical fiber locating features to provide a coupling configuration of optical fiber ends that nominally matches the photodetector configuration. Finally, the corresponding-reference surface of the fiber-optic end piece is mounted against the reference surface of the reference-surface block such that the coupling configuration abuts the photodetector configuration.