Patent ID: 9618708
Date: 2017-04-11
CPC Classifications: G02B

Claim:
1. An optical apparatus comprising first and second transmissive diffractive optical elements, wherein: the first and second diffractive optical elements are held in substantially fixed positions relative to one another; the first diffractive optical element includes a multiplexed transmission region characterized by a corresponding average grating-normal vector direction, a corresponding average grating wavevector magnitude, and a corresponding average grating wavevector direction; the second diffractive optical element includes multiple demultiplexed transmission regions that are spatially displaced from one another, each of which is characterized by a corresponding average grating-normal vector direction, a corresponding average grating wavevector magnitude, and a corresponding average grating wavevector direction; each demultiplexed transmission region differs from at least one other demultiplexed transmission region with respect to one or more of the grating-normal vector direction, the grating wavevector magnitude, or the grating wavevector direction; the relative positions of the first and second diffractive optical elements, the grating-normal vector directions, the grating wavevector magnitudes, and the grating wavevector directions are such that each one of a set of multiple optical signals, at corresponding different selected signal wavelengths in an operational wavelength range, co-propagating to the multiplexed transmission region along a multiplexed beam path would (i) be transmissively, dispersively diffracted by the first diffractive optical element, (ii) propagate directly, without any intervening reflection, between the multiplexed transmission region and a corresponding one of the demultiplexed transmission regions different from a demultiplexed transmission region of at least one other of the multiple optical signals, (iii) be transmissively, dispersively diffracted by the second diffractive optical element, and (iv) propagate from the corresponding demultiplexed transmission region along a corresponding one of multiple demultiplexed beam paths.