Multimode planar spectrographs for wavelength demultiplexing and methods of fabrication
AssigneeInternational Business Machines Corporation
InventorsMitchell S. Cohen, George A. Sefler, James L. Speidell
Life of this patent
Estimating the term…
Abstract
A planar spectrograph for demultiplexing optical wavelength signals includes a monolithic substrate. The substrate has a diffraction grating etched therein. The diffraction grating is integrally formed in the substrate to be in operative relationship with input light to diffract and reflect the input light to a detector. A recess is formed in the substrate to accommodate a separate slab waveguide. A slab waveguide is dimensioned and configured to fit within the recess, and the waveguide guides input light to and from the diffraction grating. A silicon-on-insulator spectrographs is also described, as well as, fabrication processes for manufacturing these spectrographs.
Claims34
A planar spectrograph for demultiplexing optical wavelength signals, comprising:
- a monolithic substrate, the substrate including:
- a diffraction grating etched therein, the diffraction grating being integrally formed in the substrate to be in operative relationship with input light to diffract and reflect the input light to a detector, wherein the substrate defines a plane and the diffraction grating includes a thickness perpendicular to the plane which is greater than or equal to a core diameter of a multimode fiber;
- and
- a recess formed in the substrate;
- and
- a slab waveguide dimensioned and configured to fit within the recess, the waveguide guides the input light to and from the diffraction grating.
A planar spectrograph for demultiplexing optical wavelength signals, comprising:
- a monolithic substrate, the substrate including:
- a diffraction grating etched therein, the diffraction grating being integrally formed in the substrate to be in operative relationship with input light to diffract and reflect the input light to a detector;
- and
- a recess formed in the substrate;
- and
- a slab waveguide dimensioned and configured to fit within the recess, the waveguide guides the input light to and from the diffraction grating,
- wherein the substrate includes a feature integrally formed therein to accept an optical fiber and wherein the substrate includes a feature integrally formed therein to accept a lens in operative relationship with the optical fiber.
A planar spectrograph for demultiplexing optical wavelength signals, comprising:
- a silicon-on-insulator (SOI) structure including a monolithic first silicon layer forming a slab waveguide core, a second substrate layer and a waveguide cladding layer disposed therebetween, the SOI substrate including:
- a diffraction grating etched in the first silicon layer of silicon down to the waveguide cladding layer, the diffraction grating being integrally formed in the first silicon layer to be in operative relationship with an input light source to diffract and reflect input light to a detector, wherein the diffraction grating includes a concave echelette grating profile.
A method for fabricating a planar spectrograph comprising the steps of:
- providing a monolithic substrate;
- lithographically patterning the substrate;
- deep etching the substrate in accordance with the lithographic pattern to integrally form a diffraction grating and a recess in the substrate, wherein the deep etching is performed to a depth equal to or greater than a core diameter of a multimode fiber;
- and
- securing a slab waveguide in the recess for directing light onto the diffraction grating and directing diffracted light from the diffraction grating.
A method for fabricating a planar spectrograph comprising the steps of:
- providing a silicon-on-insulator substrate;
- lithographically patterning the first silicon layer of the substrate;
- and
- deep etching the first silicon layer in accordance with the lithographic pattern to integrally form a diffraction grating in the first silicon layer, wherein the diffraction grating includes a concave echelette grating profile.
A method for fabricating a planar spectrograph comprising the steps of:
- providing a monolithic substrate;
- lithographically patterning the substrate;
- deep etching the substrate in accordance with the lithographic pattern to integrally form a diffraction grating and a recess in the substrate;
- securing a slab waveguide in the recess for directing light onto the diffraction grating and directing diffracted light from the diffraction grating;
- and
- applying an index matching fluid between the diffraction grating and the slab waveguide.
Dependencies are inferred from the claim text.