Polysilicon micromachined fiber-optical attenuator for DWDM applications

A high performance variable optical attenuator has been developed and its optical and mechanical models have also been established. The attenuator is fabricated by silicon surface micromachining technology and is then integrated with two single mode optical fibers that act as optical input and output. The attenuation is obtained by placing a 40 μm × 40 μm gold-coated micromirror into the light path between two fibers. The attenuator has an overall layout size of 0.6 mm × 1 mm (not including the fibers). It has 1.5 dB insertion loss and 45 dB attenuation range, and requires <8 V driving voltage to sweep the whole attenuation range. The specifications are promising for DWDM applications. The optical and mechanical models have been developed to fully characterize the VOA and therefore simplify the further design and optimization.