The authors investigate a 1 × N free-space microoptical fiber switch for a large number of interconnects. The system to be studied is a reflective 4 f optical system. Alignment tolerances and coupling efficiency are investigated and the benefit brought by collimating microlens arrays is reported (theoretically and experimentally). The use of microlenses enables power coupling efficiency between 3 and 2 dB (including losses due to the optical elements) for an optical switch allowing up to 3000 receiver fibers.