Patent ID: 7899286

Claim:
An optical coupling device comprising: a lower cladding layer formed on a substrate, light entering through a side surface of one end portion of the lower cladding layer; a stripe-like optical waveguide having a tapered distal end portion and formed on a portion of the lower cladding layer, the tapered distal end portion of the optical waveguide being directed to the one end portion of the lower cladding layer; and an upper cladding layer continuously formed on the lower cladding layer and the distal end portion of the optical waveguide from the one end portion of the lower cladding layer to the distal end portion of the optical waveguide, the upper cladding layer having a refractive index higher than that of the lower cladding layer, and configured to draw the light having entered the lower cladding layer and couple the light to the distal end portion of the optical waveguide, wherein a thickness d 1 of the upper cladding layer is defined by d 0 ≦d 1 ≦λ/n 1 where d 0 is a thickness of the optical waveguide, λ is a wavelength of the light, and n 1 is the refractive index of the upper cladding layer, and wherein a thickness d 2 of the lower cladding layer is defined by d 2 ≧λ/n 2 where λ is a wavelength of the light, and n 2 is the refractive index of the lower cladding layer.