Waveguide (optics)

About: Waveguide (optics) is a research topic. Over the lifetime, 44965 publications have been published within this topic receiving 618942 citations. The topic is also known as: lightguide & waveguide.

Photonic-bandgap microcavities in optical waveguides

Abstract: Confinement of light to small volumes has important implications for optical emission properties: it changes the probability of spontaneous emission from atoms, allowing both enhancement and inhibition. In photonic-bandgap (PBG) materials1,2,3,4 (also known as photonic crystals), light can be confined within a volume of the order of (λ/2n)3, where λ is the emission wavelength and n the refractive index of the material, by scattering from a periodic array of scattering centres. Until recently5,6, the properties of two- and three-dimensional PBG structures have been measured only at microwave frequencies. Because the optical bandgap scales with the period of the scattering centres, feature sizes of around 100 nm are needed for manipulation of light at the infrared wavelength (1.54 µm) used for optical communications. Fabricating features this small requires the use of electron-beam or X-ray lithography. Here we report measurements of microcavity resonances in PBG structures integrated directly into a sub-micrometre-scale silicon waveguide. The microcavity has a resonance at a wavelength of 1.56 µm, a quality factor of 265 and a modal volume of 0.055 µm3. This level of integration might lead to new photonic chip architectures and devices, such as zero-threshold microlasers, filters and signal routers.

Radiation-pressure cooling and optomechanical instability of a micromirror

Abstract: Cooling of mechanical resonators is the focus of much research effort because of possible applications in ultra-high precision measurements such as gravitational wave detection. It is also of fundamental interest as using this technique it may be possible to observe a transition between classical and quantum behaviour of a mechanical system. Three groups report advances in this area. Gigan et al. and Arcizet et al. used radiation pressure to freeze out thermal vibrations of tiny mechanical microresonators, or micromirrors. In the right conditions, the mirrors cool from room temperature to about 10 K without outside influence. Once the technique is refined it should be possible to achieve further cooling and to observe the quantum ground state of a micromirror experimentally. In the third paper, Dustin Kleckner and Dirk Bouwmeester use optical feedback to cool a micromirror to sub-kelvin temperatures. A micromechanical resonator is used as a mirror in a very high-finesse optical cavity, and its displacements are monitored with unprecedented sensitivity. By detuning the laser frequency with respect to the cavity resonance, a drastic cooling of the microresonator by intracavity radiation pressure is observed, down to an effective temperature of 10 kelvin. Recent table-top optical interferometry experiments1,2 and advances in gravitational-wave detectors3 have demonstrated the capability of optical interferometry to detect displacements with high sensitivity. Operation at higher powers will be crucial for further sensitivity enhancement, but dynamical effects caused by radiation pressure on the interferometer mirrors must be taken into account, and the appearance of optomechanical instabilities may jeopardize the stable operation of the next generation of interferometers4,5,6. These instabilities7,8 are the result of a nonlinear coupling between the motion of the mirrors and the optical field, which modifies the effective dynamics of the mirror. Such ‘optical spring’ effects have already been demonstrated for the mechanical damping of an electromagnetic waveguide with a moving wall9, the resonance frequency of a specially designed flexure oscillator10, and the optomechanical instability of a silica microtoroidal resonator11. Here we present an experiment where a micromechanical resonator is used as a mirror in a very high-finesse optical cavity, and its displacements are monitored with unprecedented sensitivity. By detuning the laser frequency with respect to the cavity resonance, we have observed a drastic cooling of the microresonator by intracavity radiation pressure, down to an effective temperature of 10 kelvin. For opposite detuning, efficient heating is observed, as well as a radiation-pressure-induced instability of the resonator. Further experimental progress and cryogenic operation may lead to the experimental observation of the quantum ground state of a micromechanical resonator12,13,14, either by passive15 or active cooling techniques16,17,18.

Optical Fiber Telecommunications

Abstract: S.E. Miller, Overview and Summary of Progress. P. Kaiser and D.B. Keck, Fiber Types and Their Status. D. Marcuse, Selected Topics in the Theory of Telecommunications Fibers. S.R. Nagel, Fiber Materials and Fabrication Methods. C.H. Gartside III, P.D. Patel, and M.R. Santana, Optical Fiber Cables. S.C. Mettler and C.M. Miller, Optical Fiber Splicing. W.C. Young and D.R. Frey, Fiber Connectors. D.L. Philen and W.T. Anderson, Optical Fiber Transmission Evaluation. W.J. Tomlinson and S.K. Korotky, Integrated Optics: Basic Concepts and Techniques. W.J. Tomlinson, Passive and Low-Speed Active Optical Components for Fiber Systems. S.K. Korotky and R.C. Alferness, Waveguide Electrooptic Devices for Optical Communication. T.P. Lee, C.A. Burrus, Jr., and R.H. Saul, Light-Emitting Diodes for Telecommunication. J.E. Bowers and M.A. Pollack, Semiconductor Lasers for Telecommunications. S.R. Forrest, Optical Detectors for Lightwave Communication. K. Kobayashi, Integrated Optical and Electronic Devices. J.A. Long, R.A. Logan, and R.F. Karlicek, Jr., Epitaxial Growth Methods for Lightwave Devices. N.K. Dutta and C.L. Zipfel, Reliability of Lasers and LEDs. B.L. Kasper, Receiver Design. P.W. Shumate, Lightwave Transmitters. R.G. Swartz, High Performance Integrated Circuits for Lightwave Systems. P.S. Henry, R.A. Linke, and A.H. Gnauck, Introduction to Lightwave Systems. S.S. Cheng and E.H. Angell, Interoffice Transmission Systems. D.C. Gloge and I. Jacobs, Terrestrial Intercity Transmission Systems. P.K. Runge and N.S. Bergano, Undersea Cable Transmission Systems. P.E. White and L.S. Smoot, Optical Fibers in Loop Distribution Systems. I.P. Kaminow, Photonic Local Networks.