Optical multiplexer-demultiplexer with mutually intersecting sub-gratings
AssigneeOki Electric Industry Co., Ltd.
InventorHideaki Okayama
Life of this patent
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Abstract
An optical multiplexer-demultiplexer has a diffraction grating formed from a plurality of mutually intersecting sub-gratings. Each sub-grating has a grating vector. The diffraction grating as a whole has a combined high-order grating vector equal to a sum of integer multiples of the grating vectors of the sub-gratings. The diffraction grating reflects incident optical signals by Bragg reflection. The difference between the propagation vector of an incident optical signal and the propagation vector of the reflected optical signal is equal to the combined high-order grating vector. A small change in wavelength of the incident optical signal can therefore produce a large change in propagation direction of the reflected optical signal.
Claims18
An optical multiplexer-demultiplexer having a diffraction grating by which optical signals of different wavelengths are reflected with different angles of reflection by Bragg reflection, the diffraction grating comprising:
- a plurality of mutually intersecting sub-gratings, each having a plurality of perturbing elements, the perturbing elements of each one of the sub-gratings intersecting the perturbing elements of the other ones of the sub-gratings, the sub-gratings having respective grating vectors, the diffraction grating having a combined high-order grating vector equal to a sum of integer multiples of the grating vectors of the sub-gratings, and the diffraction grating being structured such that an incident optical signal having a first propagation vector is reflected by the diffraction grating to yield a reflected optical signal having a second propagation vector, with the second propagation vector and the first propagation vector having a difference equal to the combined high-order grating vector.
Dependencies are inferred from the claim text.