A device is provided. The device may be an optical device, a light coupling device, or a device containing an optical structure. The device includes a waveguide, a cladding, and a light coupling material. The light coupling material is disposed adjacent to the waveguide and has a first surface and a second surface, where the second surface is disposed further away from the waveguide than the first surface and a thickness of the second surface is greater than that of the first surface.