Patent ID: 7565041
Filing Date: 2009-07-21
Classification: G02B

Abstract:
1. A Mach-Zehnder circuit, comprising: a first directional coupler; a second directional coupler; and first and second arms provided between the first and second directional couplers, the first arm including a waveguide having a length extending in a first direction and a width extending in a second direction transverse to the first direction, the waveguide including, first, second and third portions, the third portion being provided between the first and second portions, wherein the width of the waveguide is substantially uniform in the third portion, the width of the waveguide in the first portion narrows in the first direction such that the first portion includes a first tapered part, and the width of the waveguide in the second portion narrows in the first direction such that the second portion includes a second tapered part, the second portion being configured to rotate a polarization of light propagating in the first direction in the waveguide.