A fiber-optic temperature sensor has been fabricated by sputtering a silicon film, together with some protective overlayers, directly onto the end of an optical fiber. The approximately one- micrometers thick silicon film serves as a Fabry-Perot etalon whose resonant wavelengths vary as functions of temperature due to changes in the film's refractive index. To manufacture a sensor with adequate long-term stability, the initially amorphous silicon film must be annealed. Laser annealing has been found to be a promising means to stabilize the silicon film's structure without degrading the optical fiber's protective buffer coating.