Fabrication method of sub-micrometer size planar gap for the micro fabry-perot interferometer

This paper reports on a fabrication method of sub-micrometer size tunable planar gaps for micro Fabry-Perot interferometers. We made an upper unit with a movable sub-micrometer step and a lower unit, separately. The upper unit was picked up and transferred to the lower unit by the stamping apparatus, and bonded to the lower unit by fusion bonding. Since the force during fusion bonding acts within a few nanometers only, the sub-micrometer size planar gap can be built. By using this fabrication method, we fabricated the 850 nm gap with a movable planar mirror of 500 mum in diameter. The gap was changed from 825 nm to 1020 nm by applying the voltage of 24 V.