A Fiber Variable Optical Attenuator Made by a Large-Stroke Polymeric Deformable Mirror

In this letter, we report a cost-effective variable optical attenuator made by a large-stroke deformable mirror (DM). The DM consists of a 1-mm-circular polymeric membrane, which is actuated by electrostatic force from an electrode underneath it. There are photoresist pillars between the polymeric membrane and the electrode to cause squeeze damping so that the response time is reduced to 1.2 ms. The polymeric deformable is aligned with a dual fiber collimator to perform optical attenuation by 3-D beam spoiling effect. The maximum dynamic range is 30 dB with 0.16-dB/V resolution. The maximum voltage is 188 V and the power consumption is 160 muW. The 0.46-dB insertion loss is achieved at 1550-nm wavelength. The polarization-dependent loss and wavelength-dependent loss are 0.25 dB and 0.5 dB, respectively, over the conduction band.