Heteroepitaxially Integrated Compound Semiconductor Optical Devices with On-Chip Waveguides

A method of making a photonic integrated circuit, the method comprising:

• depositing a first cladding layer on a silicon substrate;
• forming a first waveguide on the first cladding layer;
• depositing a second cladding layer on the first waveguide;
• etching a trench through the second cladding layer, at least a portion of the first waveguide, and the first cladding layer, wherein etching through the first waveguide forms a first end of the first waveguide;
• epitaxially growing a III-V semiconductor material in the trench;
• and
• forming a second waveguide from at least a portion of the III-V semiconductor material, the second waveguide having a second end that is vertically aligned with and butt-coupled to the first end of the first waveguide.