Optical switch driven by giant magnetostrictive thin films

Abstract

Optical 1xN 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 1xN 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 degree was achieved under stable switching operation and was considered to increase the number of communication channels for construction of fiber optical network application.