Feasibility study of self-assembly mechanism for variable optical attenuator

This paper describes the feasibility study result for a variable optical attenuator (VOA) realized by a new concept of self-assembled polysilicon structures and a continuously position-controllable curved beam actuator based on surface micromachining technology. The self-assembly mechanism includes a residual stress induced curved beam which lifts up the reflective mirror shutter first. This self-assembled reflective pop-up shutter is locked and fixed on a curved polysilicon beam actuator which is connected with a polysilicon frame clamped on the substrate. Secondly, a set of polysilicon scratch drive actuators drives the frame, curved beam actuator and shutter moving forward and sliding into the space between the two ends of the input and output fiber ports. The optical attenuation range of the proposed VOA is determined by the vertical position of the self-assembled reflective shutter which is controlled depending on the applied voltage value. This new VOA has demonstrated continuous attenuation capability and wide attenuation range. This device demonstrates 70 dB attenuation range and less than I dB insertion loss.