# US 8,542,960 B2 · Tunable ring resonator > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,542,960 B2 - Document ID: US8542960B2 - Status: Granted - Kind: B2 - Application number: 12/262,419 - Filed: 2008-10-31 - Published: 2009-09-24 - Granted: 2013-09-24 - Earliest claimed: 2008-03-19 - Assignees: Hewlett-Packard Development Company, L.P. - Applicants: David Fattal; Sagi Mathal; Marco Fiorentino; Charles Santori; Robert G Walmsley - Inventors: David Fattal; Sagi Mathal; Marco Fiorentino; Charles Santori; Robert G Walmsley - Web page: https://patentgrep.com/patent/US8542960B2 ## CPC - G02B 6/12007: {forming wavelength selective elements, e.g. multiplexer, demultiplexer} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract A ring resonator has a first optical waveguide arranged in a loop, a second optical waveguide tangentially optically coupled to the first optical waveguide, and a translatable body configured to selectively move into an evanescent field region of said first optical waveguide. ## Claims ### Claim 1 A ring resonator, comprising: a first optical waveguide arranged in a loop; a second optical waveguide that is tangentially optically coupled to said first optical waveguide; a first doped semiconductor region, said first doped semiconductor region being surrounded by said loop of said first optical waveguide and electrically coupled to a first electrode that extends from said first doped semiconductor region across a portion of said first optical waveguide; a second doped semiconductor region disposed outside of said loop of said first optical waveguide, said second doped semiconductor region being electrically coupled to a second electrode such that a selectively applied voltage between said first and second electrodes selectively injects or removes charge from said first optical waveguide; and a translatable body configured to selectively move into an evanescent field region of said first optical waveguide, said translatable body comprising a curved portion configured to substantially overlap a majority of said first optical waveguide without crossing said first electrode. ### Claim 2 (depends on 1) The ring resonator of claim 1, wherein said translatable body comprises a microelectromechanical system (MEMS) actuator. ### Claim 3 (depends on 1) The ring resonator of claim 1, wherein said translatable body comprises a dielectric constant greater than 1.3. ### Claim 4 (depends on 1) The ring resonator of claim 1, wherein said translatable body comprises a semiconductor material. ### Claim 5 (depends on 1) The ring resonator of claim 1, wherein said first and second optical waveguides are fabricated out of a semiconductor material. ### Claim 6 (depends on 1) The ring resonator of claim 1, further comprising a substrate; wherein said optical waveguides are disposed on said substrate and said first and second doped semiconductor regions are formed within said substrate. ### Claim 7 (depends on 1) The ring resonator of claim 1, further comprising an optical source and photodetector optically coupled with said second optical waveguide. ### Claim 8 An optical system, comprising: a ring resonator having; a first optical waveguide arranged in a loom; a second optical waveguide that is tangentially optically coupled to said first optical waveguide; a first doped semiconductor region, said first doped semiconductor region being surrounded by said loop of said first optical waveguide and electrically coupled to a first electrode that extends from said first doped semiconductor region across a portion of said first optical waveguide; a second doped semiconductor region disposed outside of said loop of said first optical waveguide, said second doped semiconductor region being electrically coupled to a second electrode; and a translatable body configured to selectively move into an evanescent field region of said first optical waveguide, said translatable body comprising a curved portion configured to substantially overlap a majority of said first optical waveguide without crossing said first electrode; and a controller configured to selectively tune a resonant frequency of said ring resonator by selectively controlling a position of said translatable body and modulate light transmitted through said ring resonator by selectively applying a voltage between said first and second electrodes. ### Claim 9 (depends on 8) The optical system of claim 8, wherein said controller is configured to adjust a resonant frequency of said ring resonator by selectively moving said translatable body with respect to said evanescent field region of said first optical waveguide. ### Claim 10 (depends on 9) The optical system of claim 9, wherein said controller is configured to selectively apply an electrostatic potential to said translatable body to selectively move said translatable body with respect to said evanescent field region. ### Claim 11 (depends on 9) The optical system of claim 9, further comprising a sensor for sensing the resonant frequency of said ring resonator, wherein said controller is configured to control said translatable body based on output from said sensor. ### Claim 12 (depends on 8) The optical system of claim 8, wherein said first and second optical waveguides are fabricated out of a semiconductor material. ### Claim 13 (depends on 8) The optical system of claim 8, wherein said translatable body comprises a dielectric constant greater than 1.3. ### Claim 14 (depends on 8) The ring resonator of claim 8, wherein said translatable body comprises a semiconductor material. ### Claim 15 (depends on 8) The optical system of claim 8, further comprising an optical source in communication with said second optical waveguide. ### Claim 16 (depends on 8) The optical system of claim 8, further comprising a substrate, wherein said first and second optical waveguides are disposed on said substrate and said first and second doped semiconductor regions are formed within said substrate. ### Claim 17 A method of selectively tuning a ring resonator, said method comprising: providing an optical ring resonator having: an optical waveguide arranged in a loop; a first doped semiconductor region, said first doped semiconductor region being surrounded by said loop of said first optical waveguide and electrically coupled to a first electrode that extends from said first doped semiconductor region across a portion of said first optical waveguide; a second doped semiconductor region disposed outside of said loop of said first optical waveguide, said second doped semiconductor region being electrically coupled to a second electrode; and a translatable body comprising a curved portion configured to substantially overlap a majority of said first optical waveguide without crossing said first electrode; and selectively altering a resonant frequency of said resonator by selectively positioning said translatable body within an evanescent field region of said optical waveguide. ### Claim 18 (depends on 17) The method of claim 17, wherein said positioning of said translatable body comprises selectively altering an electrostatic charge on said translatable body. ### Claim 19 (depends on 17) The method of claim 17, further comprising dynamically receiving data from a sensor that is sensing said resonant frequency of said resonator. ### Claim 20 (depends on 19) The method of claim 19, further comprising using said data in a feedback loop to tune said resonator to a desired resonant frequency.