Optical switch driven by giant magnetostrictive thin films

Abstract

Optical 1×N switches which can be operated by Giant Magnetostrictive Thin Film under the magnetic field are firstly investigated. Bulk micromachining and deposition of magnetostrictive thin film was used for fabrication of a 1×N cantilever-type optical switch. Optical switching operation induced by magnetostriction was examined through optical path modulation test. The optical path can be redirected and exactly positioned by wide reflection-angle change of light with cantilever deflection. Deflection of cantilever by magnetostriction was significantly improved in our developed Re-Fe thin film system. In this report, Giant magnetostrictive thin films of amorphous Tb-Fe and Sm-Fe based alloys exhibiting excellent magnetostrictive characteristics at low magnetic fields are developed from a systematic investigation with a particular emphasis being placed to examine B effects. Magnetostrictions of 173 ppm and - 585 ppm are achieved in B containing Tb-Fe and Sm-Fe thin films, respectively, at a magnetic field of 100 Oe. Switching characteristics of our cantilever-type optical switch were evaluated using optical fiber under laser-optic test system. Optical path change of 6° was achieved under stable switching operation and was considered to increase the number of communication channels for construction of fiber optical network application.