An optical attenuator has a planar MEMS substrate supporting two optical fibers; an actuator; and a silicon vane actuatable by said actuator for a movement into and out of the optical beam passed between the fibers. The vane is configured to divert at least a portion of the optical beam off the optical axis when the element is moved into the optical beam. The vane has at least one surface disposed non-perpendicularly relative to the optical axis of the beam. The vane may be of a wedged shape.