OPTI510R: Photonics Khanh Kieu College of Optical Sciences, University of Arizona kkieu@optics.arizona.edu Meinel building R.626
Announcements Homework #2 is due Feb. 12 Mid-term exam will be on Feb. 28 No class Monday Feb. 26 Pre-record lecture Friday Feb. 23 at 2PM Discussion of guided wave optics starts today continues for a few weeks Classical optics Guided wave optics Lasers and detectors
Guided-wave optics Introduction Overview of guided-wave devices Planar waveguides Optical fibers Integrated optical devices Compact lasers High power fiber lasers Planar mirror waveguides Waveguide modes Dispersion relation
Introduction Light goes in a straight path after each optical element. Can we make light to follow a curved path?
Introduction Electron can follow curved paths! Integrated circuit
Yes, light can be bent! John Tyndall demonstrated light guiding by total internal reflection in the 1800s. Tyndall Box Can we create integrated circuits for photons?
Devices that curve light
Why guided wave optics? Propagate light over long distances without the need for lenses Escape the slavery of diffraction Take advantage of semiconductor manufacturing processes to determine dimensions and designs Enable unique devices impossible to make in other ways (arrayed waveguide grating) Drive the size of photonics down dramatically (compact silicon photonics devices)
Why guided wave optics? Ti:sa femtosecond laser Femtosecond fiber laser
Important trends Integrated optical circuits: combination of multiple optical functions on a single substrate Functions include splitting, filtering, switching, modulating, isolating, coupling (general passive functions), generation (lasers) and detection Monolithic integration a single material is used Hybrid integration multiple materials are used that perform different functions Optoelectronic integrated circuits (OEIC) Includes both integrated optical circuits and conventional electronic circuits on the same substrate Generally limited to semiconductor substrate materials High refractive indices create the potential for ultracompact circuitry Increasing need for optical interconnections between and within computers
Waveguides Optical fibers Waveguide and ring resonator Silicon photonics chip Optoelectronics chip
Why is it important? Data transmission bottleneck Credit: A. Scherer
Why is it important? 100x Power Trends in Communication Networks-JSTQE VOL. 17, NO. 2, MARCH/APRIL 2011
Energy saving Picture of a data center
Energy saving Inside a Google data center
Energy saving Inside a Google data center
Energy saving Microsoft is experimenting with underwater data centers Source: The Verge
Energy saving From Prof. J. Bower
Energy saving From Prof. J. Bower
Overview of waveguide devices Optical fibers Planar waveguides Integrated optical devices Compact lasers High power fiber lasers
Working principles Reflection from mirrors Total internal reflection Photonics bandgap
Waveguide geometries Slab waveguide Channel waveguide Cylindrical waveguide optical fiber Photonics crystals
Light-guiding with optical fibers Optical fiber around the globe Source: Fortune
Light-guiding with optical fibers Brief history 1841: Daniel Colladon demonstrates light guiding in jet of water Geneva 1842: Jacques Babinet reports light guiding in water jets and bent glass rods Paris 1880: William Wheeler invents system of light pipes to illuminate homes from an electric arc lamp in basement, Concord, Mass. January 2, 1954: Hopkins and Kapany and van Heel publish separate papers in Nature. Hopkins and Kapany report imaging bundles of unclad fibers; van Heel reports simple bundles of clad fibers December 8, 1956: Curtiss makes first glass-clad fibers by rod-intube method May 1961: Elias Snitzer of American Optical publishes theoretical description of single-mode fibers July 1966: Kao and Hockham publish paper outlining their proposal in the Proceedings of the Institution of Electrical Engineers Summer 1970: Maurer, Donald Keck, Peter Schultz, and Frank Zimar at Corning develop a single-mode fiber with loss of 17 db/km at 633 nanometers by doping titanium into fiber core (credit: J. Hecht)
Singlemode optical fiber Silica cladding 8mm Doped silica core 125mm Width of human hair ~ 100mm
Integrated optical devices Lasers Modulators Mux/Demux Fibers Amplifiers Detectors Can we shrink this down to a small chip?
Silicon waveguides High Q silicon resonator Silicon modulator (IBM)
Integrated optical devices Silicon photonics
Integrated optical devices 1000 km Credit: E. Mounier
Integrated optical devices It is just the beginning! Credit: IME
Fast progress Hybrid Silicon Photonic Integrated Circuit Technology JSTQE-INV-SL-04600-2012
Light sources Standard telecom diode laser
On-chip Raman laser Can we make a laser out of Silicon? Credit: M. Paniccia
On-chip Raman laser Credit: M. Paniccia
Hybrid Silicon Laser Hybrid Silicon Photonic Integrated Circuit Technology JSTQE-INV-SL-04600-2012
Nano-lasers Still quite low efficiency and output power Optically pumped Still a remaining challenge!
Fiber lasers Photonics spectra IPG Photonics
Fiber lasers
Questions for Thoughts What do you want to do after graduation? Can you come up with a laser on a silicon wafer? A new light-guiding principle? A Mega-Watt fiber laser? Can we create an Optics computer?