Magnetically actuated MEMS variable optical attenuator

Abstract

A novel magnetically driven single mode fiber micro-electro-mechanical systems (MEMS) variable optical attenuator operating in the 1550-nm wavelength region is described. The device consists of a planar coil type electromagnetic microactuator, a ferronickel attenuation vane, and fiber alignment components with V-shaped grooves. The microactuator consists of a silicon spring, a planar coil, and permalloy membrane. The planar coil was fabricated by high aspect ratio photolithography and mask-plating process. The silicon spring and the fiber alignment components were fabricated by reactive ion etching and by the silicon anisotropic etching process. A new technique, termed non-silicon surface micromachining, was used to fabricate the attenuation vane, which uses copper layer as the sacrificial layer, and the electroplated ferronickel as the structure layer. The magnetic, mechanical and optical characteristics of the attenuator were theoretically analyzed and simulated. The MEMS attenuator has less than 3-dB fiber-to-fiber insertion loss at 1550-nm wavelength, greater than 40-dB dynamic range, and better than 40dB return loss.