Optics and Photonics Concentration

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Optics and Photonics Concentration

  1. 1. Optics and Photonics Georgia Institute of Technology - Atlanta School of Electrical and Computer Engineering
  2. 2. Optics and Photonics Core Faculty  Ali Adibi  John A. Buck  Russ Callen  Gee-Kung Chang  Affiliated members  David S. Citrin  Ian T. Ferguson  Christiana Honsberg Microsystems  Thomas K. Gaylord  William Hunt BioEngineering  Elias N. Glytsis  Mary Ann Ingram Telecommunications  Bernard Kippelen  Glenn Smith Electromagnetics  Stephen E. Ralph  Ajeet Rohatgi Microsystems  William T. Rhodes  Steve McLaughlin Telecom  Gisele Bennett  Douglas Yoder Microsystems GTRIP  Ben Klein
  3. 3. Primary Research Areas Optical Communication Networks  Next generation optical networks  Optical networking testbeds  Advanced modulation formats  Optical and electronic mitigation of signal impairment  Coherent and interferometric detection  Equalization and coding with telecommunications faculty Nonlinear Optics  Propagation in optical fibers and nonlinear effects in semiconductors  Wavelength conversion methods  Propagation of ultrashort solitons,  Nonlinear propagation in fiber amplifiers  Continuum generation in microstructure fiber.  Short pulse characterization techniques which reveal both the amplitude and phase
  4. 4. Primary Research Areas Photonics and optoelectronics  Integrated sensors  Fundamental investigations of new materials and nanostructures  High speed optical transmitters, receivers  Lithium niobate modulators with integrated drivers and detection  Photonic bandgap devices: optical interconnects, signal processing, and computing.  Photonic crystals with 1-D, 2-D, and 3-D bandgap structures, for passive and active optical devices Diffractive and holographic optics  Volume holograms for data storage (memory), 3D pattern recognition, filtering, WDM, interconnection, and sensing  Diffractive/holographic optical elements, perform functions that would be very difficult or impossible to produce using conventional optics.  Driven by fundamental improvements in modeling, design, and optimization methods as well as advances in microfabrication technology
  5. 5. Georgia Tech Lorraine Quantum optical signal transmission Photon counting for long distance transmissions with very weak optical beams (1 photon/bit) Non-linear dynamics for generating random codes for spread- spectrum communications and multiple access networks Soliton modulation, wavelength division multiplexing Signal coding for wireless communications Efficient conversion of 2- and 3-D full-spectral image information Secure communications by means of quantum optics and chaotic generation of random encryption keys
  6. 6. Advanced Methods for Terahertz Science and Engineering TERAHERTZ TECHNOLOGYWith Doug Denison, Mike Knotts, John Schultz, Don Creyts, Electromagnetic SpectrumDavid Citrin, Stephen Ralph 100 GHz 10 THz OBJECTIVES RF and Microwave IR, Optical, X-ray • Expand recognized RF and optical capabilities to Science TERAHERTZ Engineering cover Terahertz frequency region • Support current research programs in metamaterials Carrier and EM composites characterization dynamics • Provide advanced THz measurement resource for Georgia Tech community Imaging • Increase RI collaborations, publications and innovations to attract new sponsored research RESEARCH DESCRIPTION IMPACT OF WORKTerahertz Science:• Development of efficient sources and detectors• Understanding of THz/material interactions • Supports GTRI strategic plan for growth into new• Integration of semiconductor simulations with full EM technology areas field numerical routines • Promotes active area of scientific research that bridges high frequency electronics and opticsTerahertz Engineering: • Secures new funding in biomedical research,• Spectroscopy of large organic molecules and nanotechnology, industrial process monitoring, and composites defense and national security applications• Imaging for biomedicine and national security
  7. 7. Ultrafast Nano-Optics Theory and Simulation David S. Citrin School Of Electrical and Computer Engineering Georgia Institute of Technology Atlanta, Georgia 30332-0250
  8. 8. Terahertz technology window and opportunities  Medical imaging  Biochemical sensing  Security  Satellite-to-satellite communications  Process monitoring  Direct modulation
  9. 9. Terahertz Nonlinearities in Semiconductor OpticalAmplifiers (SOA) Time dependent carrier temperature in GaAs SOA follows THz frequency
  10. 10. Magneto-Optical Sensors:Semiconductor Nanorings InAs nanorings: Petroff group: UCSB
  11. 11. Localized Correlators for Mode Separation inMultimode Fibers Ali Adibi School of Electrical and Computer Eng. Georgia Institute of Technology
  12. 12. Applications of Two-Center Recording• Gated holographic recording ⇒ Localized recording  Data storage  Optical elements Conventional optical elements Diffractive optical elements  Optical correlator Pattern recognition Mode separation (MM fibers)
  13. 13. Localized Holographic Correlators Reference Sensitizing Detector Array Recording Correlation Different patterns are recorded in different slices Diffracted intensity is proportional to the correlation between the reading pattern with the recorded one
  14. 14. Research AreasFundamental physical processes Applications  charge generation  Organic displays  charge transport  Photovoltaic cells  electroluminescence  RFID tags and sensors  optical amplification  Organic field-effect transistors  lasers  Organic memories  photorefractivity  Real-time holography  nonlinear-optics  Electro-active lenses  liquid crystal mesophases  Imaging
  15. 15. Organic Photovoltaics Bottom-up approach to photovoltaic cells on light weight flexiblesubstrates Develop new organic semiconductors with high mobility Use self-assembly to produce highly ordered thin films
  16. 16. Organic Electronics Low temperature processing of organic semiconductors, metals and dielectrics on flexible substrates: low cost ($0.01)  Macroelectronics  RF identification tagsMetal deposition on plastics  Electronic paperfrom solution, micro-sizefeatures using soft lithography  Active matrix drivers
  17. 17. Organic Displays  RGB active high luminance at low voltage, processing at low temperature on flexible substrates  Developed photo-patternable hole transport polymers that can be processed like a photoresist; provides easy patterning for color displays.Chem. Mater. 15, 1491 (2003)
  18. 18. Holography and Imaging Thick phase recording media for real-time holography, large dynamic range and video rate compatible response times  Holographic storage  Optical correlators  Dynamic holograms  Image processing  Medical Imaging  Optical testing  Novelty filtering  Phase-conjugation
  19. 19. Nonlinear Optics & Photonics  Organic electro-optic materials and devices  Frequency conversion  Tunable filters and routers  Tunable optical delay lines  Amplifiers and lasers  Short pulse diagnostics  Integrated waveguide and microring resonator devices
  20. 20. Optical Networking Group Goals• Establish Optical Networking Research Laboratory • Next Generation optical network architecture and applications • Design and Build Next Generation Optical Internet Testbed• Enabling Photonic System Technology Research • Advanced transmitters, receivers, modulation techniques • All-optical wavelength, space, and time switches • Tunable optical delay, optical label, and burst mode payload receivers • Compensation techniques for fiber transmission impairments• Control and Management of Optical Routing Network • Broadband access technology for bandwidth-on-demand, low-latency symmetric customer services. • OLS and GMPLS control plane and management interface • Routing protocol and contention resolution algorithms• Enhanced Intelligent Networking Services and Operations • Agile dynamic service creation, provisioning, and protection/restoration • Flexible burst switching service with flexible bandwidth granularity• Build a National Research Testbed Consortium • Lead communications research institutions • Enhance and build upon National Light (Lambda) Rails
  21. 21. Broadband Optical Networking ONU ONU Testbed Research in Georgia TechONU Access Network Splitter/ Combiner Core Network Node RWA OLSR RWA OLT WDM WDM IP/MPLS IP/MPLS ADM ports RWA ADM ports Edge Network WDM Edge Network Node RWA Node IP/MPLS WDM RWA IP/MPLS WDM ONU ADM ports ADM portsOptical Router ONUArchitecture Backplane OLT -X S bE PO C O G Splitter/ M&CN Optical label Combiner Nλ ’s Extraction Client Interface Processor Wavelength per Fiber Interchange OLSR: Optical Label Access Network ONU Incoming Outgoing Optical Traffic OLS Switching Fabric Optical Traffic Switching Router ONU Forwading Engine RWA: Routing and Routing Engine Switching Assignment Georgia Tech Confidential
  22. 22. Building Optical Networking Testbed in GCATT
  23. 23. Promoting Optical Networking for Next Generation InternetBellSouth Network Service President and CTO
  24. 24. Fully Integrated Chem/Bio SensingMultimode Interferometer/CMOS detection and signal analysis  Development of interferometric chemical and biological “wet” and gas sensors integrated directly with on-chip electronics for intelligent sensors  The key to this research is the design and fabrication of biological and chemical interferometric sensors integrated in three dimensions (3D) directly on top of Si CMOS VLSI detector and signal processing circuitry  The challenge for this integrated system is to demonstrate high sensitivity detection in a miniaturized, short Si CMOS on-chip size, and species discrimination in a rugged, low power, portable format Silicon PiN diode array for modal image analysis Sigma-Delta “analog to digital” converters Heterogeneous integrated laser sources
  25. 25. Interferometer Structure Reference SensingSensing Layer: Detects organics, i.e. benzene, trichloroethylene Compatible with electronics fabrication and processing Chemically resistant Reusable (reversible sorption or organics) Novolac ~1 µm, n ~1.60 Si3N4 ~0.2 µm, Effective up to 250 °C n ~ 1.9218, k ~ 0 Index of refraction = 1.59 – 1.61 (l = 850 nm) SiO2 cladding ~2 µm, n ~ 1.4734, k ~ 0 Available dissolved in solvent for spin coating Silicon Substrate, n ~ 3.6538, k ~ 0.004177
  26. 26. A Platform Technology for the Integration ofSemiconductor Electronic Devices with NonlinearOptical Materials Stephen E. Ralph W. Alan Doolittle stephen.ralph@ece.gatech.edu alan.doolittle@ece.gatech.edu 404 894 5168 404 894 9884 Georgia Institute of Technology School of Electrical and Computer Engineering 777 Atlantic Drive Atlanta GA 30332
  27. 27. Dense Epitaxial Integrated OpticsSignal processing circuits Electrodes Epitaxial III-Nitride Epitaxial AlN bufferTi diffused/strip loadedwaveguides LiNbO3  Georgia Tech has developed a materials growth technology which allows the epitaxial integration of AlGaN semiconductors with the most widely used nonlinear-electro optical material, Lithium Niobate  This technology enables:  Integrated control of phase and amplitude of optical signals  Advanced modulation formats exploiting phase, commonly seen in wireless  Interferometric transmitters and receivers  Integrated detection at 1500nm via use of InN detectors  Monitoring of Extinction ratio  Dynamically adaptable bias point control  Dynamic Chirp control  Pulse shaping
  28. 28. Source Progress in Device Processing Gate DrainProcess ProtectionProcess Protection SiNX Waveguide Electrodes Modulation doped cap Modulation doped AlGaN cap Undoped GaN Undoped GaN “Special”AlN “Special” AlN Z-cut LiNbO3 Ti-diffused wafers Z-cut LiNbO3 Ti-diffused wafers Waveguides •Students have been trained and have successfully completed 7 out of 16 process steps. Source •Aggressive small geometry lithography and metallization (1-4 um) successfully demonstrated. Gate Drain Source Drain •New students began training and clean room qualification (~3 month process) in fall 2003. Mesa •Effort leveraged by engineer supported outside of GTBI program.
  29. 29. Soliton Generation via IntrapulseStimulated Raman Scattering in Photonic Crystal Fibers: Experimental and Numerical Investigations B.R. Washburn, S.E. Ralph School of Electrical and Computer Engineering Georgia Institute of Technology P. A. Lacourt, J. M. Dudley, W. T. Rhodes GTL-CNRS Telecom, Georgia Tech Lorraine S. Coen Service d’Optique et Acoustique, Université Libre de Bruxelles R.S. Windeler Bell Laboratories, Lucent Technologies
  30. 30. Geometry of the Photonic Crystal Fiber• PCF comprised of a hexagonal lattice of air-holes and glass• The “core” is a defect in the lattice: glass where a hole should be• PCF exhibits a reduced fiber core size compared to standard fiber• The effective nonlinearity (γ=0.07(W m)−1 ) is eight times larger than in 2020ncrωγ≡π standard fiber at 800 nm• Specific geometry exhibits zero group velocity dispersion at 767 nm
  31. 31. Supercontinuum Generation in PCF 100 10-1 10-2 10-3 Supercontinuum Generation Spectral Intensity (a.u.) 10-4 Input Ti:sapphire 10-5 spectrum 600 700 800 900 1000 1100 1200 1300 1400 Wavelength (nm)  Dramatic spectral broadening due to multiple nonlinear effects (SPM, FWM, SRS) occurring simultaneously  Dominant mechanism depends on peak power, pulse width and dispersion and fiber length  Spectral width of 1000 nm, which covers all visible wavelengths
  32. 32. Cooperative Signal Processing for Equalization Stephen E. Ralph and Steve Mclaughlin School of Electrical and Computer Engineering
  33. 33. Fabricated Device V cc Two-segment metal-semiconductor- metal (MSM) device fabricated  InGaAs and GaAs demonstrated -Vcc Vo  Ease of manufacture  50-µm inner detector radius Vcc Scalar weighting is implemented by Vcc applying dual-biasing Separate Optical Detection Regions  “Polarity” of detected signal is related Fiber to polarity of bias voltage Vo Maintains the simplicity of a conventional photodetector -Vcc
  34. 34. Channel Impulse Response Simulation Measurement λ = 1550 nm λ = 1550 nm λ = 810 nm λ = 810 nm Measured with ~1-ps @ 1550-nm or ~20-ps @ 810-nm Assume incoherent interaction among modes are output Fiber: 1.1-km silica MMF with 50-µm graded-index core  Simulation parameter of fiber based on manufacture specs
  35. 35. Simulated Eye-Diagram over 1.1-km MMF 600-Mbps @ 810-nm 1250-Mbps @ 1550-nm Emulate MMF link by using measured MMF impulse response with conventional PD 600-Mbps @ 810-nm 1250-Mbps @ 1550-nm Emulate MMF link by using measured MMF impulse response with SRE enhancement200 MHz-km @ 810-nm 500 MHz-km @ 1550-nm
  36. 36. Measured 1.25-Gbps Link Link with 1.1 km, 50-µm, GI-MMF  PRBS at 1.25-Gb/s Externally modulated 1550-nm FP laser source with mode-scrambler  Overfilled-launch into fiber Dramatic reduction in ISI with SRE  Improvement in amplitude and phase margin  Complete closure of eye otherwise  Works synergistically with restricted illumination condition
  37. 37. Measured Bit-Error-Rate * includes penalty associated with non- optimized performance inherent to receiver (PD responsivity, TIA noise, PD-TIA response) For 1.1-km link, >10-9 BER at 1.25 Gbps is achievable with SRE  With standard detection, ISI renders link unusable Despite SRE loss, sensitivity required for 1000-LX Ethernet is achievable  Back-to-back; accounting for penalty due to non-optimal device fabrication
  38. 38. 1.1km MMF Link Performance @ 1.25 Gbps  Combined techniques “SRE+DFE” and “SRE + Viterbi” shows unique capabilities of an integrated Photonic/Electrical Approach pioneered at Georgia Tech  Near total compensation of DMD is possibleDFE = 5 forward taps, 5 backward taps Viterbi = 16 states, 20 bits decoder depth

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