Patent ID: 7330630
Filing Date: 2008-02-12
Classification: G02F

Abstract:
1. A waveguide type variable optical attenuator, comprising: a substrate for forming a waveguide for optical signal propagation; a waveguide element comprising a first arm waveguide and a second arm waveguide arranged on a surface of the substrate for constituting a portion of the waveguide and cladding for covering the first and second arm waveguides and the surface of the substrate; an output side waveguide connecting the first arm waveguide with the second arm waveguide and arranged to couple light from the first arm waveguide with light from the second arm waveguide; and a heater arranged on a surface of the waveguide element for heating the first and second arm waveguides, wherein: the first and second arm waveguides and the output side waveguide constitute one optical interference circuit, the first and second arm waveguides are connected thermally to each other by a high thermal-conductivity member that covers the heater, the high thermal-conductivity member being different from the heater.