Patent ID: 7860358
Filing Date: 2010-12-28
Classification: G02B,G02F

Abstract:
1. A multimode interference waveguide type optical switch comprising: an input single-mode waveguide into which input light is entered; a multimode rectangular slab waveguide into which light emitted from the input single-mode waveguide is entered; two electrodes that are arranged in parallel in a waveguide direction on the slab waveguide and that decrease the refractive index of the slab waveguide disposed thereunder by injecting current or applying voltage; and a plurality of output single-mode waveguides into which light emitted from the slab waveguide is entered and from which output light is emitted, all of said waveguides being arranged in the same direction, wherein: a connection end between the input single-mode waveguide and the slab waveguide and a connection end between a first output single-mode waveguide and the slab waveguide are arranged in a point-symmetric manner with respect to a center of a rectangle formed by a straight line along an inner side surface of a first electrode, a straight line along a side surface of the slab waveguide farther from the first electrode, a straight line that passes through the connection end between the input single-mode waveguide and the slab waveguide and that is perpendicular to the waveguide direction, and a straight line that passes through the connection end between the first output single-mode waveguide and the slab waveguide and that is perpendicular to the waveguide direction, and a connection end between the input single-mode waveguide and the slab waveguide and a connection end between a second output single-mode waveguide and the slab waveguide are arranged in a point-symmetric manner with respect to a center of a rectangle formed by a straight line along an inner side surface of a second electrode, a straight line along a side surface of the slab waveguide farther from the second electrode, a straight line that passes through the connection end between the input single-mode waveguide and the slab waveguide and that is perpendicular to the waveguide direction, and a straight line that passes through the connection end between the second output single-mode waveguide and the slab waveguide and that is perpendicular to the waveguide direction, said multimode interference waveguide type optical switch further comprising tapered waveguides between the input single-mode waveguide and the slab waveguide and/or between the slab waveguide and the output single-mode waveguide.