Patent ID: 9110348
Filing Date: 2015-08-18
Classification: G02B,G02F

Abstract:
1. An optical element comprising an optical waveguide comprising a core formed from: a rib part; and a first and second slab parts which are located on both sides of the rib part so as to sandwich the rib part and thinner than the rib part, wherein the rib part and the first and second slab parts of the core are integrally formed by a semiconductor single crystal, the first slab part comprises a P-type region which is doped to be P type, the second slab part comprises an N-type region which is doped to be N type, the rib part comprises a P-type region which is in contact with the P-type region provided in the first slab part, and an N-type region which is in contact with the N-type region provided in the second slab part, the P-type region and the N-type region of the rib part are in contact with each other to constitute a PN junction part, the rib part comprises a top portion which is located above the first and second slab parts in a cross section perpendicular to the longitudinal direction of the optical waveguide, and the top portion of the rib part comprises an undoped region formed from at least one of an intrinsic region and a low-concentration doping region which is doped at a dopant concentration 1/10 or less of a dopant concentration in at least one of the adjacent P-type region and the adjacent N-type region.