VARIABLE OPTICAL ATTENUATOR

摘要

PURPOSE: A variable optical attenuator is provided to have a small driving voltage and to improve an extinction rate of an optical signal. CONSTITUTION: A variable optical attenuator includes an optical wave-guide(121) having an electric-optical or thermal-optical properties and a clad(122) surrounding the optical wave-guide, attenuating an optical signal proceeding into the optical wave-guide. The optical wave-guide includes a curve optical wave-guide for changing an index of refraction depending on the amount of an external energy. The external energy is a current or a voltage. The curve optical wave-guide is an optical wave-guide having a circular arc. The optical wave-guide consists of a ferroelectrics or a material of III - V groups or II - VI groups.