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US 2008/0166095 A1Published application
Fabrication-tolerant waveguides and resonators
AssigneeMassachusetts Institute of Technology
InventorsMilos Popovic, Tymon Barwicz
Life of this patent
Estimating the term…
Abstract
An optical waveguide having a core region with a substantially rectangular cross-section with a selected aspect ratio of width to height. Embodiments include devices incorporating the optical waveguide and methods for using the optical waveguide.
Claims35
A device comprising:
- an optical waveguide including:
- a first core region disposed over a substrate, the first core region having a first substantially rectangular cross-section and comprising a first core material, the first core material comprising a semiconductor and being substantially transparent within an operating wavelength range having a first free-space center wavelength;
- and
- a first cladding region surrounding the first core region, the first cladding region (i) comprising at least one cladding material having a refractive index, and (ii) having a first maximum cladding refractive index equal to the largest refractive index of the at least one cladding material,
- wherein the first rectangular cross-section has a first aspect ratio AR defined by a ratio of a width of the first rectangular cross-section to a height of the first rectangular cross-section, the first aspect ratio is at least 5:1, and a height of the first core region is between 1/150 and 1/10 of the first free-space center wavelength.
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The ring filter of claim 25, wherein the ring filter is tunable, further comprising:
- a heating element associated with the ring resonator, the heating element being disposed in proximity to the ring resonator at a distance to the optical waveguides of the ring resonator (i) sufficiently small to facilitate substantial transfer of heat from the heating element to the optical waveguides, and (ii) sufficiently great to avoid substantial absorbance by the heating element of optical radiation propagating through the optical waveguides.
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A method of propagating optical signals through a waveguide with low loss and low device sensitivity to fabrication imperfections, the method including the steps of:
- providing an optical waveguide having a substantially rectangular cross-section with an aspect ratio defined by a ratio of width to height of at least 5:1, the cross-section supporting a single mode;
- and
- propagating light in the optical waveguide solely in the single mode.
A method of propagating optical signals through a waveguide with low loss and low device sensitivity to fabrication imperfections, the method including the steps of:
- providing an optical waveguide having a cross-section with an aspect ratio of width to height of about 1.8:1, the cross-section supporting at least two TE modes and only one TM mode, and the optical waveguide having at least one TE mode with a higher effective index than the TM mode;
- and
- propagating light in the optical waveguide solely in the TM polarized mode.
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A device comprising:
- an optical waveguide including:
- a core region having a substantially rectangular cross-section and comprising a core material, the core material being substantially transparent within an operating wavelength range having a free-space center wavelength;
- a cladding region surrounding the core region, the cladding region (i) comprising at least one cladding material having a refractive index, and (ii) having a maximum cladding refractive index equal to the largest refractive index of the at least one cladding material,
- wherein the rectangular cross-section has an aspect ratio defined by a ratio of a width of the rectangular cross-section to a height of the rectangular cross-section, and the aspect ratio is less than 3:4.
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A method of propagating optical signals through a waveguide with strong lateral optical confinement and low bending loss, the method including the steps of:
- providing an optical waveguide having a cross-section with an aspect ratio of width to height of less than about 3:4, the cross-section supporting only one TM mode;
- and
- propagating light in the optical waveguide solely in the TM polarized mode.
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A device comprising:
- a first and a second optical waveguide, the first optical waveguide comprising:
- a first core region disposed over a substrate, the first core region having a first substantially rectangular cross-section and comprising a first core material, the first core material comprising a semiconductor and being substantially transparent within an operating wavelength range having a first free-space center wavelength;
- and
- a first cladding region surrounding the first core region, the first cladding region (i) comprising at least one cladding material having a refractive index, and (ii) having a first maximum cladding refractive index equal to the largest refractive index of the at least one cladding material,
- wherein (i) the first rectangular cross-section has an aspect ratio defined by a ratio of a width of the rectangular cross-section to a height of the rectangular cross-section, (ii) the aspect ratio is at least 1.8:1, (iii) the aspect ratio, the height, and the width of the core region cross-section cooperate to support a single TM mode and more than one TE mode.
- and the second optical waveguide is coupled to the first optical waveguide, the second optical waveguide including:
- a second core region having a second substantially rectangular cross-section and comprising a second core material, the second core material comprising a semiconductor and being substantially transparent within an operating wavelength range having a second free-space center wavelength, and
- a second cladding region surrounding the second core region, the second cladding region (i) comprising at least one cladding material having a second cladding refractive index, and (ii) having a second maximum cladding refractive index equal to the largest refractive index of the at least one cladding material,
- wherein (i) the second rectangular cross-section has an aspect ratio defined by a ratio of a width of the rectangular cross-section to a height of the rectangular cross-section, (ii) the aspect ratio is at least 1.8:1, (iii) the aspect ratio, the height, and the width of the core region cross-section cooperate to support a single TM mode and more than one TE mode.
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Dependencies are inferred from the claim text.