The VOAD series variable optical attenuators feature direct drive by a function generator having bandwidth up to 1.5 kHz, providing attenuation up to >30 dB. It is a convenient tool for laboratory use. Driving voltages of 0 to 8 V control optical transmission without polarity, which decreases with applied voltage with modulation up to 1.5 kHz. Most voltage sources, including power supplies, function generators, and digital-to-analog converters (DACs), can be used to control these electronic VOAs. The MEMS VOA is an electrostatic device that requires little current. However, the device can be damaged by applying a voltage over 15 V. The VOA is optically bidirectional.