Adopting advanced thick film & thin film technology through firing at the high temperature of 850 ℃. ● Temperature compensation and RF isolation, which are more suitable for multi-stage. An optical attenuator, or fiber optic attenuator, is a device used to reduce the power level of an optical signal, either in free space or in an optical fiber. The basic types of optical attenuators are fixed, step-wise variable, and continuously variable. Unlike a fixed attenuator, which imposes a constant loss, a VOA allows the loss to be adjusted from nearly zero up to tens of decibels.