Ring_cavities - Fibers and Ring Resonators Cornell Nanophotonics Group http/nanophotonics.ece.cornell.edu Cornell Nanophotonics Group

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Unformatted text preview: Fibers and Ring Resonators Cornell Nanophotonics Group http://nanophotonics.ece.cornell.edu Cornell Nanophotonics Group http://nanophotonics.ece.cornell.edu Cornell Nanophotonics Group http://nanophotonics.ece.cornell.edu Ring Resonators Cornell Nanophotonics Group http://nanophotonics.ece.cornell.edu 2 − ⋅L 2 2 T eα − 1 κ − − ⋅L⋅ 1 κ = − /1 eα − Cornell Nanophotonics Group http://nanophotonics.ece.cornell.edu Ring Cavities Cornell Nanophotonics Group http://nanophotonics.ece.cornell.edu Strong Light Confining Structures , Q of the device: Cornell Nanophotonics Group http://nanophotonics.ece.cornell.edu 20 µ m 2 − ⋅L 2 2 α T e − 1 κ − − ⋅L⋅ 1 κ = − /1 eα − Critical coupling: Cornell Nanophotonics Group http://nanophotonics.ece.cornell.edu Ring Cavities Cornell Nanophotonics Group http://nanophotonics.ece.cornell.edu Cornell Nanophotonics Group http://nanophotonics.ece.cornell.edu Strong Light Confining Structures , Cornell Nanophotonics Group http://nanophotonics.ece.cornell.edu 20 µ m Cornell Nanophotonics Group http://nanophotonics.ece.cornell.edu All-Optical Modulation Control (pump) Opening gate: from opaque to transparent Cornell Nanophotonics Group http://nanophotonics.ece.cornell.edu Switching Light on Silicon Using Free-Carriers Mechanism: Plasma Dispersion Effect (linear process) Refractive index change by free carrier injection ∆n = ∆ne + ∆nh = −[8.8 × 10 −22 ⋅ ∆N + 8.5 × 10 −18 ⋅ ( ∆P ) ] 0.8 Challenge: Weak index dependence on free carrier concentration R.A. Soref, et al , IEEE Journal of Quantum Electronics, vol. 23, (1987) Cornell Nanophotonics Group http://nanophotonics.ece.cornell.edu Cornell Nanophotonics Group http://nanophotonics.ece.cornell.edu Compact all-optical modulator on Silicon 0.2µ m Waveguide Ring , High confinement waveguides: Enhancement of the two-photon absorption High Q cavity: Increase in sensitivity of the device to small index changes Pump+probe (λ probe~ λ pump~1.5µm) Almeida, V. R., Barrios, C. A., Panepucci, R. R., Lipson, M., “All-Optical control of light on a Silicon chip”, Nature, pp1081-1084 (Oct 28th, 2004) Almeida, V. R., Barrios, C. A., Panepucci, R. R., Lipson, M., Foster, M.A., Quzounov, D. G., and A. L. Gaeta, “All-optical switching on a silicon chip”, Optics Letters 29 (Dec. 2004) Cornell Nanophotonics Group http://nanophotonics.ece.cornell.edu Demonstration of Switch: Opening Gate Pump on ∆τ=0.1psec Pump off Probe transmission 100 Pump off Transparent Probe transmisison Probe wavelength (nm) 50 Opaque 0 0 400 ps 1 2 Opaque 3 Time (ns) fJ power consumed Almeida, V, Lipson, M., Nature, p1081 (Oct, 2004) Control (pump) Cornell Nanophotonics Group http://nanophotonics.ece.cornell.edu Ring Resonator Based Electro-Optic Ring Modulator on Silicon-on-Insulator-microns in Modulator on size size Liu, A. et al. Nature 427, 615 (2004) Q. Xu, B. Shcmidt, M. Lipson, Nature, May 19 March 2005 Cornell Nanophotonics Group http://nanophotonics.ece.cornell.edu Fabrication Scanning electron micrograph of a ring resonator Width = 450nm Ebeam Lithography Si: 250nm BOx: 3μm Si Substrate Etching using RIE BOx: 3μm Si Substrate Oxide Deposition EBeam Resist Width = 450nm Gap = 200nm Diameter = 12μm BOx: 3μm Si Substrate Via Hole Etching and Ion Implantation p+ (B) n+ (As) BOx: 3μm Si Substrate Contact Metallization Microscope image of fabricated optical modulator with electrical contacts BOx: 3μm Si Substrate Cornell Nanophotonics Group http://nanophotonics.ece.cornell.edu Modulation results (DC) Cornell Nanophotonics Group http://nanophotonics.ece.cornell.edu Dynamic response 0.4 Gbit/s generated with 3.3 Vpp in micron-size device! Lifetime under junction: 0.2nsec Q. Xu, B. Shcmidt, M. Lipson, Nature, May 19 March 2005 Cornell Nanophotonics Group http://nanophotonics.ece.cornell.edu THz Modulators S. Manipatruni, M. Lipson, et al., LEOS 2007 Cornell Nanophotonics Group http://nanophotonics.ece.cornell.edu ...
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