Organic amorphous fluoropolymer membrane for variable optical attenuator applications

The paper describes the design, fabrication and testing of a MEMS (micro-electro-mechanical systems) variable optical attenuator (VOA) made from an organic fluoropolymer thin film. The optical attenuation is achieved by changing the radius of curvature of the organic thin film by actuating a pneumatic force. The size of the organic polymer membrane is 4 mm × 4 mm and the measured centre displacement of the organic membrane is as large as 57 μm without any plastic deformation. The mechanical deformation of the fluoropolymer membrane can be simulated by finite element method (FEM) and the optical coupling efficiency is calculated based on the coherent optical transfer function (OTF) of the deformed membrane. The experimental results show that the attenuation range can achieve 25 dB at the wavelength of 1550 nm, which agrees well with the theoretical calculation. The measured wavelength dependence loss is less than 0.5 dB.