A variable optical attenuator based on optofluidic technology

A novel variable optical attenuator based on optofluidic technology has been fabricated and demonstrated. Light attenuation is caused by the optical absorbing capability of liquid and the modulation can be achieved by changing the liquid dimension in the optical transmission path. In our design, this is done by the deformation of an air-controlled membrane and its subsequent contact with a rigid plate. From the results, it can be seen that nearly 38 dB dynamic range and 0.479 dB insertion loss can be achieved and the polarization-dependent loss (PDL) is also demonstrated to be less than 0.4 dB in the whole working range.