Optical coupling module, photoelectric conversion device and optical communication device

The invention relates to an optical coupling module which comprises a substrate, a first waveguide, a second waveguide and a grating. The first waveguide, the second waveguide and the grating are formed in the substrate. The substrate is provided with a top surface and a bottom surface. The first waveguide is provided with a first end and a first connecting part. The second waveguide is provided with a second end and a second connecting part. The second connecting part and the first connecting part are crossed and are partially overlapped for forming an overlapping part. After connection of the first waveguide and the second waveguide, a formed member is Y-shaped. The first end and the second end respectively have an oblique end surface. Each oblique end surface is connected with the top surface and inclines in the direction to the bottom surface relative to the top surface. Each oblique end surface is trapezoidal. The width of each oblique end surface in a direction which is parallel with the top surface gra