Patent ID: 6990261

Claim:
An optical circuit device comprising: a substrate of a III–V group compound semiconductor; and a magnetic semiconductor layer formed on the substrate, substantially lattice matching with the substrate and having the chalcopyrite type crystal structure, wherein the magnetic semiconductor layer is formed of a compound of (T 0.5 IV 0.5 ) x III 1−X V type, a compound of T 0.5 (IV X IV′ 1−X ) 0.5 V type, a compound of T 0.5 IV 0.5 V x V′ 1−X type, a compound of (II X T 1−X ) 0.5 IV 0.5 V type or a mixed compound of said compounds, in which T represents a transition metal element; II indicates a II group element; III denotes a III group element; IV and IV′ represent a IV group element; and V and V′ indicate a V group element.