A LIGA fabricated latching, bistable magnetic micro actuator for optical fiber switching and other applications

A bi-directional, latching magnetic micro actuator has been designed and fabricated and applied to optical fiber switching. This is the first device which has successfully incorporated permanent magnets in a linear micro actuator application. The actuator produced a maximum throw of 174 μm, switching and latching forces of greater than 2.2 mN and fiber placement accuracy in the 0.1 μm range.; The linear actuator moves along one axis of motion based on current polarity in an electromagnetic coil. The flux provided by the coil interacts with that provided by two permanent magnets by either opposing or aiding the flux using a novel magnetic device concept which produces the force that switches the actuator between two stable states. The bistable switch has stable positions at either end of the actuator's travel obtained through the use of shaped electromagnetic poles and plungers and permanent magnets. When power is removed from the electromagnetic coil the switch remains in its current position, biased by the magnetic flux provided by the permanent magnets.; The LIGA process was used to fabricate the device using electroplated NiFe as the structural material. The permanent magnets were fashioned by micro electro-discharge machining. High precision optics alignment hardware was cofabricated and assembled next to the switch.; The operation of the device has been verified; measured performance matches theoretical expectations. The device latches in both directions and obtains a minimum switching speed of 2.21 ms for drive currents in the normal operating range, between 5.88 mA and 8.83 mA. The device was found to operate at currents below this range if switching from the latched position rather than from the equilibrium position of the recoil springs. Power dissipated by the switch within the normal operating region was as low as 11 mW and within the subthreshold region the power was as low as 6 mW. The latch was incorporated as the driving actuator for a 1 x 2 single mode optical fiber switch. Insertion loss of the optical fiber switch was measured to be as small as 0.5 dB without the use of optical index matching fluid.