Optical power splitter and method of manufacturing the same

An optical device comprising:

• a substrate;
• a first optical layer on the substrate, wherein the first optical layer comprises a top surface, a first sidewall and a second sidewall opposite to the first sidewall;
• a high k layer disposed on the top surface of the first optical layer;
• and
• a second optical layer on the high k layer, wherein the second optical layer comprises a top surface, a third sidewall and a fourth sidewall opposite to the third sidewall, wherein the first optical layer includes a Transverse Magnetic (TM) transmission mode and the second optical layer includes a Transverse Electric (TE) transmission mode, and wherein when the first optical layer and the second optical layer project on the substrate, a projection area of the second optical layer falls within a projection area of the first optical layer from a top view, wherein the high k layer fully covers the top surface of the first optical layer, wherein the high k layer comprises a fifth sidewall and a sixth sidewall opposite to the fifth sidewall, wherein the third sidewall of the second optical layer is recessed from the fifth sidewall of the high k layer.

A method for manufacturing an optical device comprising:

• forming a substrate;
• forming a first optical layer on the substrate;
• forming a high k layer on the first optical layer;
• and
• forming a second optical layer on the high k layer, wherein a projection area of the second optical layer falls within a projection area of the first optical layer from a top view, wherein a material of the substrate includes SiO2 and a material of the first optical layer and the second optical layer includes SiN, wherein the high k layer fully covers the top surface of the first optical layer.