Disclosed are various embodiments of a reflective optical encoder having at least three channels—two data channels and one index channel—disposed along a common axis or single track. The single track configuration disclosed herein permits very high resolution reflective optical encoders in small packages to be provided. In addition, the single track configuration reduces problems with misalignment between code scales and light detectors, permits relatively simple electronic circuitry to be used to process outputs, and reduces manufacturing, assembly, integrated circuit and encoder costs. Methods of making and using such optical encoders are also disclosed.