# US 12,038,605 B2 · Wave guide sensor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,038,605 B2 - Document ID: US12038605B2 - Status: Granted - Kind: B2 - Application number: 17/513,575 - Filed: 2021-10-28 - Published: 2022-02-17 - Granted: 2024-07-16 - Earliest claimed: 2019-04-29 - Assignees: Universite Claude Bernard Lyon 1; Centre National De La Recherche Scientifique; Institut National Des Sciences Appliquees De Lyon; STMicroelectronics (Crolles 2) SAS - Applicants: STMicroelectronics (Crolles 2) SAS; Institut National des Sciences Appliquees de Lyon; Universite Claude Bernard Lyon 1; Centre National de la Recherche Scientifique - Inventors: Michele Calvo; Stephane Monfray; Paul Charette; Guillaume Beaudin; Regis Orobtchouk - Web page: https://patentgrep.com/patent/US12038605B2 ## CPC - G01N 21/7703: {using reagent-clad optical fibres or optical waveguides (using measurement of total internal reflection or attenuated total reflection G01N21/552; optical fibres or waveguides per se G02B)} - G02B 6/1226: {involving surface plasmon interaction} - G01N 15/06: Investigating concentration of particle suspensions (by weighing G01N5/00; investigating sedimentation of particle suspensions G01N15/04; investigating individual particles G01N15/10) - G01N 21/553: {and using surface plasmons (fluorescence excitation G01N21/648; enhanced Raman G01N21/658)} - G02B 5/008: {Surface plasmon devices (diffractive gratings with a pitch less than or comparable to the wavelength G02B5/1809; surface plasmons in integrated optics G02B6/1226; optical analysis of materials by means of surface plasmons G01N21/553)} - G02B 6/13: Integrated optical circuits characterised by the manufacturing method - G01N 15/075: by optical means - G01N 2021/4126: {Index of thin films} - G01N 2021/5903: {using surface plasmon resonance [SPR], e.g. extraordinary optical transmission [EOT]} - G02B 2006/12138: {Sensor} - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract An embodiment sensor includes a hybrid waveguide. The hybrid waveguide includes a first dielectric optical waveguide lying on and in contact with a dielectric support layer; a first surface waveguide optically coupled to the first dielectric optical waveguide, parallel to the first dielectric optical waveguide, and lying on the dielectric support layer. The first surface waveguide has a lateral surface configured to guide a surface mode. The hybrid waveguide includes a cavity intended to be filled with a dielectric fluid, separating laterally the first dielectric optical waveguide from the lateral surface of the first surface waveguide. ## Claims ### Claim 1 A sensor comprising: a hybrid waveguide comprising: a first dielectric optical waveguide lying on and in contact with a dielectric support layer; a first surface waveguide optically coupled to the first dielectric optical waveguide, parallel to the first dielectric optical waveguide, and lying on the dielectric support layer, the first surface waveguide comprising a lateral surface configured to guide a surface mode, the first surface waveguide comprising a metal layer and a substrate layer made of a different material than the metal layer, the metal layer covering the substrate layer and comprising the lateral surface; and a cavity intended to be filled with a dielectric fluid, separating laterally the first dielectric optical waveguide from the lateral surface of the first surface waveguide. ### Claim 2 (depends on 1) The sensor according to claim 1, wherein the first surface waveguide is a plasmonic waveguide and being configured to propagate surface plasmons. ### Claim 3 (depends on 1) The sensor according to claim 1, wherein the hybrid waveguide is configured to guide an optical mode of an optical signal when the dielectric fluid fills the cavity, and covers the first dielectric optical waveguide and the first surface waveguide. ### Claim 4 (depends on 3) The sensor according to claim 3, wherein an effective optical index of the optical mode in the hybrid waveguide is higher than an refractive index of the dielectric fluid and than an effective optical index of the optical mode in the first dielectric optical waveguide on its own. ### Claim 5 (depends on 3) The sensor according to claim 3, wherein the optical mode is a radiated mode of the first dielectric optical waveguide predominantly from longitudinal lateral faces of the first dielectric optical waveguide. ### Claim 6 (depends on 1) The sensor according to claim 1, wherein the first dielectric optical waveguide comprises a dielectric or semiconducting strip a lower face of which lies on and in contact with an upper face of the support layer and longitudinal lateral faces of which constitute the longitudinal lateral faces of the first dielectric optical waveguide. ### Claim 7 (depends on 1) The sensor according to claim 1, wherein a dimension of the cavity between the longitudinal lateral face of the first dielectric optical waveguide and the lateral surface of the first surface waveguide is less than an operating wavelength of the sensor. ### Claim 8 (depends on 7) The sensor according to claim 7, wherein the cavity extends widthways from the longitudinal lateral face of the first dielectric optical waveguide up to the lateral surface of the first surface waveguide, the lateral surface of the first surface waveguide being parallel to the longitudinal lateral face. ### Claim 9 (depends on 1) The sensor according to claim 1, comprising an annular resonant waveguide constituted entirely or partly by the hybrid waveguide. ### Claim 10 (depends on 1) The sensor according to claim 1, comprising an interferometer of a Mach-Zehnder type constituted entirely or partly by the hybrid waveguide. ### Claim 11 (depends on 1) The sensor according to claim 1, wherein faces of the first dielectric optical waveguide intended to be in contact with the dielectric fluid or faces of the first surface waveguide intended to be in contact with the fluid are functionalized as a function of a molecule or a particle to be detected in the fluid. ### Claim 12 (depends on 1) The sensor according to claim 1, adapted to detect, in the fluid, a molecule or a particle of a size of up to 5 μm. ### Claim 13 A method comprising: determining, by simulation of a hybrid waveguide of a sensor comprising a dielectric optical waveguide lying on a dielectric support layer and being surrounded by a dielectric fluid, dimensions of a transverse section of a first dielectric optical waveguide, the simulation of the sensor being performed without accounting for any surface waveguide, the dimensions being determined such that, for an optical mode of a signal propagating in the first dielectric optical waveguide, an effective optical index of the optical mode is lower than an refractive index of the dielectric fluid; determining, by simulation of the sensor in which the transverse section of the first dielectric optical waveguide has the determined dimensions, a position of a first surface waveguide with respect to the first dielectric optical waveguide so that an effective optical index of the optical mode in the hybrid waveguide is greater than the refractive index of the dielectric fluid; and manufacturing the sensor with the determined dimensions and the determined position, wherein the sensor comprises a hybrid waveguide comprising: a first dielectric optical waveguide lying on and in contact with a dielectric support layer; a first surface waveguide optically coupled to the first dielectric optical waveguide, parallel to the first dielectric optical waveguide, and lying on the dielectric support layer, the first surface waveguide comprising a lateral surface configured to guide a surface mode, the first surface waveguide comprising a metal layer and a substrate layer made of a different material than the metal layer, the metal layer covering the substrate layer and comprising the lateral surface; and a cavity intended to be filled with a dielectric fluid, separating laterally the first dielectric optical waveguide from the lateral surface of the first surface waveguide. ### Claim 14 (depends on 13) The method according to claim 13, wherein the first surface waveguide is a plasmonic waveguide, the lateral surface of the first surface waveguide being of metal and being configured to propagate surface plasmons. ### Claim 15 (depends on 13) The method according to claim 13, further comprising guiding an optical mode of an optical signal when the dielectric fluid covers the first dielectric optical waveguide and the first surface waveguide. ### Claim 16 (depends on 13) The method according to claim 13, wherein the first dielectric optical waveguide comprises a dielectric or semiconducting strip a lower face of which lies on and in contact with an upper face of the support layer and longitudinal lateral faces of which constitute the longitudinal lateral faces of the first dielectric optical waveguide. ### Claim 17 A method of forming a sensor comprising a hybrid waveguide, the method comprising: forming an optical waveguide disposed over a dielectric support layer; forming a first plasmonic waveguide and a second plasmonic waveguide disposed over the dielectric support layer, the first plasmonic waveguide being oriented along a first lateral surface of the optical waveguide, the second plasmonic waveguide being oriented along a second lateral surface of the optical waveguide, the first plasmonic waveguide comprising a first material and a second material made of a different material than the first material, the first material covering a sidewall of the second material facing the optical waveguide, the first material forming a lateral surface of the first plasmonic waveguide; and forming a first cavity disposed between the first plasmonic waveguide and the optical waveguide and a second cavity disposed between the second plasmonic waveguide and the optical waveguide, the first cavity being configured to be filled with a dielectric fluid and the second cavity being configured to be filled with the dielectric fluid. ### Claim 18 (depends on 17) The method according to claim 17, wherein forming the first plasmonic waveguide and the second plasmonic waveguide and forming the first cavity and the second cavity comprises: conformally depositing a metal layer over the optical waveguide, forming an etch mask over the metal layer, and removing portions of the metal layer not covered with the etch mask to form the first plasmonic waveguide and the second plasmonic waveguide along with the first cavity and the second cavity. ### Claim 19 (depends on 17) The method according to claim 17, wherein forming the optical waveguide, forming the first plasmonic waveguide and the second plasmonic waveguide, and forming the first cavity and the second cavity comprises: forming a first feature corresponding to the optical waveguide, a second feature corresponding to the first plasmonic waveguide, and a third feature corresponding to the second plasmonic waveguide over the dielectric support layer; forming a conformal liner over the first, the second, and the third features; forming a etch mask covering the conformal liner, the etch mask covering portions of the conformal liner over the second and third features; and removing the portions of the conformal liner exposed by the etch mask. ### Claim 20 A method of forming a sensor comprising a hybrid waveguide, the method comprising: forming an optical waveguide disposed over a dielectric support layer; forming a first plasmonic waveguide and a second plasmonic waveguide disposed over the dielectric support layer, the first plasmonic waveguide being oriented along a first lateral surface of the optical waveguide, the second plasmonic waveguide being oriented along a second lateral surface of the optical waveguide; and forming a first cavity disposed between the first plasmonic waveguide and the optical waveguide and a second cavity disposed between the second plasmonic waveguide and the optical waveguide, the first cavity being configured to be filled with a dielectric fluid and the second cavity being configured to be filled with the dielectric fluid, wherein forming the optical waveguide, forming the first plasmonic waveguide and forming the first cavity comprises: forming a first feature corresponding to the optical waveguide over the dielectric support layer; forming a pattern comprising a first material selectively etchable with respect to the first feature, the first material covering sidewalls and top surface of the first feature; forming a conformal liner over the pattern and exposed surfaces of the dielectric support layer; forming a second material over the conformal liner; using a planarizing process, opening a top surface of the first feature and forming a second feature comprising a portion of the second material and the conformal liner; forming an etch mask over the second feature; performing an etching process to remove the pattern exposed after forming the etch mask; and removing remaining etch mask to form the first cavity and the first plasmonic waveguide from the second feature.