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ARAVIND SURESH(Roll no:09) S7A EC. SILICON PHOTONICS. SILICON PHOTONICS. OVERVIEW. Introduction Optoelectronics at present WDM AWG and WDM Siliconize photonic Stimulated Raman Amplification The Raman effect Laser
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ARAVIND SURESH(Roll no:09) S7A EC SILICON PHOTONICS
SILICON PHOTONICS OVERVIEW • Introduction • Optoelectronics at present • WDM • AWG and WDM • Siliconize photonic • Stimulated Raman Amplification • The Raman effect Laser • Silicon laser • Modulator • Coding of optical data • Photodetector • Interface • The silicon challenges • Applications • Futurescope & Conclusion • Reference COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS INTRODUCTION • Moore’s Law(1962) • Presently 1.7billion transistors • More transistors more information can process • Copper wires are used to communicate between peripheral devices • Wires close to each other can induce currents in one another • Increased resistance=increased heat =decay of data • Microscopic imperfection, Skin effect, Proxmity effect • Data speed > 10Gbps not achieved • Replace copper with optical fiber and electron with photon COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS OPTOELECTRONICS AT PRESENT • A single fiber strand can now carry up to 14Tbps • Send pulses of light instead of pulses of electron current in guided medium • Fibre Optics immune to attenuation- repeaters at over 100 Kms • Pack dozens of channels by separating channel by wave length-WDM “Wave length division multiplexing” • Use lasers to shoot light pulses through glass fibers • Need of coherent light COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS WDMThe wavelength division multiplexing • Multiplexing upto 160 channels • Bandwidth in the range : 1260-1675 nm • Single Mode Fibre core diameter only- 9 micrometer • Channel separation as low as 0.8 nm • Most commonly used is: C-band transmission window : 1530-1565 nm • Uses AWG (de)multiplexer COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS AWG and WDM • Array of waveguides with constant length increment • Diffraction and Interference play the role • Advantages-low loss,low cost,ease of network upgrading • Precision Temperature control: +/-2 Degree C COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS SILICONIZE PHOTONICS • Means all components are integrated on the silicon chip • To siliconize photonic – • A integrated light source • Device that split, route and direct light on silicon chip • Modulator to encode data into optical signal • Photo detector to convert the optical signal back to electrical bits • Low cost high volume assembly methods • Supporting electronic for intelligence and photonic control COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS MILESTONES • All-Silicon Laser- • Silicon is an indirect bandgap material • Need an external source for initial light • Problem of misalignment of external laser • Raman effect 10,000 times stronger in silicon. • STIMULATED RAMAN SCATTERING (SRS) AMPLIFICATION • Intel disclosed development of first continuous wave all-silicon laser(2005) To be continued… COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS SRS Stimulated Raman Scattering • Pump Laser-500 mW,980nm • Weak Data beam-1550nm(C-band) • Data beam energy passed to molecular vibration • Pump photon absorption • High energy photon emission and wavelength shift • Scattering reduced in C-band • Advantage COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS The Raman effect LASER COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS Silicon laser • Need wave guide for light beam • Two photons absorption • Silicon to absorb pump beam’s photon and release free electrons • Electron cloud reduce amplification • P-I-N diode in silicon laser • Dielectric mirrors in silicon laser COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS Silicon laser COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS Modulator • Modulation –switching one state to another state(on and off) • Two types of modulation Direct modulation -direct switching of source(on-off)-limit 10Gbps~12km External modulation -used for 10Gbps~100km+ • Each time laser turn on it ’chirps’-un desired shift in wavelength-data distortion • Use external modulator chirp free -use lithium nobate-strong electro optic effect • External Phase modulation of light without disturbing source COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS Modulation COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS Encoding optical data(ASK-digital modulation) The Mach–Zehnder interferometer • Split the laser into two • Apply electric field to one beam • Speed changes and out of phase • When recombine- result cancel out • No electric field apply -No speed variation and same phase • When recombine beam encoded with 1’s and 0’s COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS MILESTONES continued… • Silicon Modulator in GHz range • Early injectioncurrent modulator- diode switching • Free carrier plasma dispertion effect. • Difficulty to extract carriers out of the path.. • 20MHz limit for silicon modulator-a limit for silicon photonics • Intel demonstrated the first GHz silicon modulator(2005) • Speed upto 10 Gbps demonstrated with transistor like device to inject as well as pull out carriers • Speed upto 18Gbps demonstrated with optical ring modulator • Disclosed the development of 40Gbps silicon modulator COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS Photo detector/Demodulation • Collect the photons and convert into electrical signal • Semiconductor diode detectors-the frontrunners -The PIN diode detector -The Avalanche Photodiode detector • InGaAs-least bandgap • Avalanche detectors with built in amplification due to intense electric field • Noise, dark current and photocurrent fluctuations • Response time-0.5ns typical COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS Demodulation & Detection COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS INTERFACE • The construct-Silicon on insulator • Connecting an optic fibre • Silicon chip-optic fibre interconnection COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS SILICON CHALLENGES • Kerr Nonlinearity effect • Refractive index varies proportional to square of electric field intensity • Four wave mixing • Three waves scatter at a point to produce fourth wavelength COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS APPLICATIONS • Integrating into a Tera-scale system • Shrinking electronic/medical equipments • 3D ICs An artistic view COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS FUTURESCOPE & CONCLUSION • Intel moving on steps towards 50Gbps optical link • Optical Revolution in:- ELECTRONICS AND COMMUNICATION ENGINEEERING COLLEGE OF ENGINEERING CHENGANNUR
SILICON PHOTONICS REFERENCES • www.ieeexplore.ieee.org- Lipson, M.; Optical Fiber communication/National Fiber Optic Engineers Conference, 2008.;Publication Year: 2008 , Page(s): 1 - 3 • techresearch.intel.com • domino.research.ibm.com • en.wikipedia.org • Ebook on Silicon Photonics – Mario Paniccia (Intel Director, Photonics Lab) • Fibre Optic Communication – Harold Kolimbiris,Scenior This Seminar Ends here Thank You All COLLEGE OF ENGINEERING CHENGANNUR