A new technique for the manufacture of miniature Fabry-Perot interferometers in silicon for use in the near-infra-red region is described. Tuning and parallelism control were achieved electrostatically, yielding low drive voltages and finesses exceeding 90 at 1.4 μm. Such devices will prove useful for laser intracavity elements and wavelength demultiplexers in fibre telecommunication systems.