Micro optical-fiber switches using magnetic actuators

In the present study, a micro plate-type reflective mirror was designed and fabricated by using surface micromachining techniques. First, a commercial MEMS foundry (MCNC MUMPs) process was used to fabricate a polysilicon plate, which served as a mirror. A layer of soft magnetic material (permalloy, Ni₈₀Fe₂₀) was then electroplated on top of the polysilicon plate by using post-fabrication process. The interaction between an external magnetic field and the permalloy generated a torque to rotate the polysilicon plate, which was supported by two torsional beams with a low modulus. Hence, the mirror could be rotated out of plane under the existence of the external magnetic field. In order to rotate the plate to a very large angle, the geometry of the supporting beams has been appropriately designed. Experimental data showed that the micro mirror was robust enough to be rotated up to 90° for over 10,000 times without any damage. In addition to a reflective mirror, several novel micro-mechanisms including vertical-positioning, horizontal-positioning and anti-interference devices have also been integrated to improve the performance of the micro optic fiber switch. A prototype of a 3 × 3 arrayed optic fiber switch has been demonstrated in this study.