Optical modulator and method of manufacturing optical modulator

An optical modulator comprising:

• a first mesa waveguide extending in a first direction, wherein the first direction is an optical axis direction;
• and
• a second mesa waveguide,
• wherein the first mesa waveguide includes a p-type first semiconductor layer disposed over a substrate, a core layer disposed over the p-type first semiconductor layer, a p-type second semiconductor layer disposed over the core layer, and an n-type third semiconductor layer disposed over the core layer, and
• wherein the p-type second semiconductor layer and the n-type third semiconductor layer are arranged adjacent to each other in the first direction;
• an electrode is disposed over the n-type third semiconductor layer;
• and
• a joining surface between the p-type second semiconductor layer and the n-type third semiconductor layer is inclined with respect to a surface orthogonal to the first direction at an angle of 50° or more to 60° or less.