Patent ID: 6304687
Filing Date: 2001-10-16
Classification: G02B

Abstract:
A lightwaveguide circuit including a plurality of waveguides of different lengths, whereineach of said waveguides comprises a lower clad, a core and an upper clad,each of said waveguides has at least one groove formed by removing said upper clad and said core from said waveguides, and a groove formed by removing said upper clad, said core and said lower clad from said waveguides, said grooves provided with a material having a temperature coefficient of a refractive index different from a temperature coefficient of an effective refractive index of said waveguides, andwherein adjacent waveguides satisfy the equation(L1-L2).times.(dn1/dT)=(L2'-L1').times.(dn2/dT)where L1' denotes the sum in lengths of said grooves of one waveguide of said plurality of waveguides,L2' denotes the sum of lengths of said grooves of another waveguide adjacent said one waveguide,L1 denotes lengths of said one waveguide which remained without said L1',L2 denotes lengths of said another waveguide which remained without said L2',dn1/dT denotes said temperature coefficient of said effective refractive index of said waveguides, anddn2/dT denotes said temperature coefficient of said effective refractive index of said material.