# US 2010/0165352 A1 · Adiabatic tapered composite waveguide for athermalization > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2010/0165352 A1 - Document ID: US20100165352A1 - Status: Published application - Kind: A1 - Application number: 12/607,892 - Filed: 2009-10-28 - Published: 2010-07-01 - Earliest claimed: 2006-09-18 - Assignees: Cyoptics Ltd. - Inventors: Sergey Frolov - Web page: https://patentgrep.com/patent/US20100165352A1 ## CPC - G02B 6/1228: {Tapered waveguides, e.g. integrated spot-size transformers (for coupling with fibres G02B6/305)} - G02B 6/12011: {characterised by the arrayed waveguides, e.g. comprising a filled groove in the array section} - G02B 6/12014: {characterised by the wavefront splitting or combining section, e.g. grooves or optical elements in a slab waveguide} - G02B 6/12028: {based on a combination of materials having a different refractive index temperature dependence, i.e. the materials are used for transmitting light} - G02B 2006/12107: {Grating} - G02B 2006/12159: {Interferometer} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract A planar waveguide circuit includes a silica-based planar optical waveguide circuit having a lower cladding, a core and an upper cladding. At least one input waveguide and one output waveguide are each coupled to the optical waveguide circuit. At least one tapered waveguide section is located in the waveguide circuit, which has an upper cladding segment that tapers down to at least the core to define a tapered recess. A filler material having a negative thermo-optic coefficient fills the tapered recess so that the optical waveguide circuit has an optical characteristic with a reduced temperature dependence. ## Claims ### Claim 1 A planar waveguide circuit comprising: a silica-based planar optical waveguide circuit having a lower cladding, a core and an upper cladding; at least one input waveguide and one output waveguide each coupled to the optical waveguide circuit; at least one adiabatic tapered waveguide section located in the waveguide circuit and having an upper cladding segment that tapers down to at least the core to define a tapered recess; and a filler material having a negative thermo-optic coefficient filling the tapered recess whereby said optical waveguide circuit has an optical characteristic with a reduced temperature dependence. ### Claim 2 (depends on 1) The planar waveguide circuit of claim 1 wherein said waveguide circuit comprises an optical filter and said optical characteristic is a transmission spectrum. ### Claim 3 (depends on 1) The planar waveguide circuit of claim 1 wherein the filler material is a polymer. ### Claim 4 (depends on 1) The planar waveguide circuit of claim 1 wherein said waveguide circuit comprises a Mach-Zehnder interferometer and said optical characteristic is a transmission spectrum. ### Claim 5 (depends on 1) The planar waveguide circuit of claim 1 wherein said waveguide circuit comprises a ring resonator filter and said optical characteristic is a transmission spectrum. ### Claim 6 (depends on 1) The planar waveguide circuit of claim 1 wherein said waveguide circuit comprises a ring resonator all pass filter and said optical characteristic is a dispersion spectrum. ### Claim 7 (depends on 1) The planar waveguide circuit of claim 1 wherein said waveguide circuit comprises a Bragg grating filter and said optical characteristic is a reflectance spectrum. ### Claim 8 (depends on 1) The planar waveguide circuit of claim 1 wherein said waveguide circuit comprises an arrayed waveguide grating having first and second free propagating optical coupling regions and an arrayed waveguide region that includes a plurality of optical waveguides optically coupling the first coupling region to the second coupling region, said optical characteristic being a transmission spectrum. ### Claim 9 (depends on 8) The planar waveguide circuit of claim 8 wherein said adiabatic tapered waveguide section is located in at least one of the free propagating waveguide sections. ### Claim 10 (depends on 8) The planar waveguide circuit of claim 8 wherein said adiabatic tapered waveguide section is located in said arrayed waveguide region. ### Claim 11 A method comprising the steps of: providing a silica-based planar optical waveguide circuit having a lower cladding, a core and an upper cladding; providing at least one input waveguide and one output waveguide each coupled to the waveguide circuit; providing at least one adiabatic tapered waveguide section located in the waveguide circuit and having an upper cladding that tapers down to a least the core to define a tapered recess; and filling the tapered recess with a filler material having a negative thermo-optic coefficient so that said waveguide circuit has a transmission spectrum with a reduced temperature dependence. ### Claim 12 (depends on 11) The method of claim 11 wherein said waveguide circuit comprises an optical filter and said optical characteristic is a transmission spectrum. ### Claim 13 (depends on 11) The method of claim 11 wherein the filler material is a polymer. ### Claim 14 (depends on 11) The method of claim 11 wherein said waveguide circuit comprises a Mach-Zehnder interferometer and said optical characteristic is a transmission spectrum. ### Claim 15 (depends on 11) The method of claim 11 wherein said waveguide circuit comprises a ring resonator filter and said optical characteristic is a transmission spectrum. ### Claim 16 (depends on 11) The method of claim 11 wherein said waveguide circuit comprises a ring resonator all pass filter and said optical characteristic is a dispersion spectrum. ### Claim 17 (depends on 11) The method of claim 11 wherein said waveguide circuit comprises a Bragg grating filter and said optical characteristic is a reflectance spectrum. ### Claim 18 (depends on 11) The method of claim 11 wherein said waveguide circuit comprises an arrayed waveguide grating having first and second free propagating optical coupling regions and an arrayed waveguide region that includes a plurality of optical waveguides optically coupling the first coupling region to the second coupling region, said optical characteristic being a transmission spectrum. ### Claim 19 (depends on 18) The method of claim 18 wherein said adiabatic tapered waveguide section is located in at least one of the free propagating waveguide sections. ### Claim 20 (depends on 18) The method of claim 18 wherein said adiabatic tapered waveguide section is located in said arrayed waveguide region.