Patent ID: 7333692

Claim:
An optical apparatus comprising: an optical transmission element; a set of diffractive elements formed in or on the transmission element; and an optical component, wherein: the diffractive element set is positioned in or on the transmission element so as to enable at least partial spatial overlap of diffractive elements of the set and an evanescent portion of an optical signal propagating in an optical waveguide suitably positioned relative to the transmission element; the optical component is arranged to launch or to receive an optical signal propagating within the transmission element; the diffractive elements of the set are arranged so as to establish optical coupling between the optical signal propagating within the transmission element and the optical signal propagating in the suitably positioned optical waveguide; and the diffractive elements of the set are arranged so that the optical signal propagating in the suitably positioned optical waveguide is successively incident on the diffractive elements of the set.