Patent ID: 7224855

Claim:
An optical apparatus, comprising: an optical element having at least one set of diffractive elements; and an optical reflector, wherein: the reflector routes, between a first optical port and a second optical port, that portion of an optical signal propagating within the optical element and transmitted by each diffractive element set; each diffractive element set routes, between a corresponding multiplexing optical port and either the first or the second optical port, a corresponding portion of the optical signal that is diffracted by the diffractive element set according to a corresponding set transfer function; and the optical element comprises a planar optical waveguide, the planar optical waveguide substantially confining in one transverse dimension the optical signal propagating in two dimensions therein, and wherein: (a) the diffractive elements of the set are collectively arranged so as to exhibit a positional variation in amplitude, optical separation, or spatial phase over some portion of the set, said positional variation determining at least in part the set transfer function; or (b) (1) each diffractive element is spatially arranged relative to a corresponding diffractive element virtual contour and comprises at least one diffracting region thereof, the diffracting regions having at least one altered optical property so as to enable diffraction of a portion of the incident optical field therefrom, (2) each diffractive element diffracts a corresponding diffracted component of an incident optical field with a corresponding diffractive element transfer function so that each diffractive element set collectively provides the corresponding set transfer function between the corresponding multiplexing optical port and either the first or the second optical port, and (3) the corresponding set transfer function or at least one corresponding diffractive element transfer function is determined at least in part by: (A) a less-than-unity fill factor for the corresponding virtual contour, (B) a non-uniform spatial distribution of multiple diffracting regions along the corresponding virtual contour, (C) variation of a spatial profile of the optical property of at least one diffracting region of the corresponding virtual contour, (D) variation of a spatial profile of the optical property among multiple diffracting regions of the corresponding virtual contour, (E) variation of the spatial profile of the optical property of at least one diffracting region among elements of at least one diffractive element set, (F) longitudinal displacement of at least one diffractive element relative to the corresponding virtual contour, or (G) at least one virtual contour lacking a diffractive element corresponding thereto.