Liquid-crystal-deflector based variable fiber-optic attenuator

A compact, low-component-count, no-moving-parts variable optical attenuator (VOA) is demonstrated for the first time by means of beam spoiling that is implemented via an electrically reconfigurable nonpixelated nematic liquid-crystal deflector. The VOA design features an in-line alignment polarization-insensitive design that does not use bulky polarization splitting and combining optics. The proof-of-concept VOA at 1550 nm demonstrates a 30-dB attenuation range, a 2.5-dB insertion loss, a ≤0.8-dB polarization-dependent loss, and a 1-s maximum attenuation reset time. The VOA design can counter performance-reducing environmental effects such as excess-loss increases due to temperature variations.