Holographic antenna gratings on optical waveguide surfaces

A holographic method is proposed for the formation of diffraction-grating couplers that focus coupled-in radiation inside a waveguide. Relationships ensuring the formation of aberration-free focusing gratings are given. A prototype structure, capable of coupling He–Ne laser radiation with λ = 1.15 μm into a waveguide and focusing this radiation to form a spot of 10 μm size, is described.