VOLTAGE CONTROLLED ATTENUATOR

摘要

A voltage controlled attenuator for an optical telecommunication system comprises an optical attenuator placed between an input and an output lens f or obstructing the path of an incoming light beam. The attenuator has variable attenuation (reflection, absorption, etc.) which is controlled for maintaining a preset power of the outgoing light beam. To this end, a fraction of the outgoing signal is diver ted to an output detector by reflecting off an end face of a lens, and processed for o btaining a control signal representative of the output power. The control signal actuat es a dc motor which displaces the attenuator to a position corresponding to a preset outpu t power.