Raman Amplifier

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<p>Raman AmplifierIntroduction Basic Raman Concept High Power Raman Fiber Lasers Raman Fiber Amplifier Combining EDFA and Raman Amplifier Conclusion</p> <p>January 8, 2008</p> <p>Y. Lin: Raman Amplifier</p> <p>1</p> <p>Introduction</p> <p>Raman Amplifier was demonstrated in the 1980s Unavailability of high-power diode laser pump source Why do you need it : amplify signals from 1270 to 1670 nm any optical fiber can serve as the amplifying medium Raman process itself provides high-power laser Disadvantage: Cross-talkJanuary 8, 2008 Y. Lin: Raman Amplifier 2</p> <p>Basic Raman Concept</p> <p>Raman scattering from molecular vibration Brillouin scattering from sound wave: Brillouin AmplifierJanuary 8, 2008 Y. Lin: Raman Amplifier 3</p> <p>Basic Raman Concept</p> <p>Spontaneous process: linear Stimulated process: Raman laser Coherent anti-Stokes scattering: Raman amplifierJanuary 8, 2008 Y. Lin: Raman Amplifier 4</p> <p>Basic Raman Concept</p> <p>Raman Spectrum from SiO2 fiberJanuary 8, 2008 Y. Lin: Raman Amplifier 5</p> <p>Basic Raman Concept</p> <p>Need high power laser Need large Raman cross section GeO2 Germania: Large Raman cross-section, refractive indexJanuary 8, 2008 Y. Lin: Raman Amplifier 6</p> <p>Raman Fiber Laser</p> <p>Higher-order Raman spectrum Laser source: Raman fiber laserJanuary 8, 2008 Y. Lin: Raman Amplifier 7</p> <p>Raman Fiber Laser</p> <p>High power are possible 5 W, 9.2 W diode-pumped Nd3+ cladding-pumped Raman fiber lasers 6.8 W diode-pumped Yb3+ cladding-pumped Raman fiber lasersJanuary 8, 2008 Y. Lin: Raman Amplifier 8</p> <p>Raman Fiber Laser</p> <p>High-order Raman scattering Partially reflecting (20%) fiber grating Eight out of ten photons are converted to the output Capable of generating high power light at any wavelength from 1.2 to 1.7 micronsJanuary 8, 2008 Y. Lin: Raman Amplifier 9</p> <p>Raman Fiber LaserHow Does Cascaded Raman Laser Work Raman Stokes Stimulated Raman Scattering Four Wave Mixing Easy phase matching</p> <p>January 8, 2008</p> <p>Y. Lin: Raman Amplifier</p> <p>10</p> <p>Raman Amplifier</p> <p>January 8, 2008</p> <p>Y. Lin: Raman Amplifier</p> <p>11</p> <p>Raman Amplifier</p> <p>Coherent anti-Stokes ScatteringJanuary 8, 2008 Y. Lin: Raman Amplifier 12</p> <p>Raman Amplifier</p> <p>Phase MatchingJanuary 8, 2008 Y. Lin: Raman Amplifier 13</p> <p>Raman Amplifier</p> <p>Amplifier GainJanuary 8, 2008 Y. Lin: Raman Amplifier 14</p> <p>Raman Amplifier</p> <p>Wide bandwidth Raman amplifier can be realized using multiple pumpsJanuary 8, 2008 Y. Lin: Raman Amplifier 15</p> <p>Raman Amplifier</p> <p>January 8, 2008</p> <p>Y. Lin: Raman Amplifier</p> <p>16</p> <p>Raman Amplifier</p> <p>Lossless transmission by Raman amplifierJanuary 8, 2008 Y. Lin: Raman Amplifier 17</p> <p>Raman Amplifier</p> <p>Walk-off due to wavelength mismatch in a pulsed Raman amplifier</p> <p>January 8, 2008</p> <p>Y. Lin: Raman Amplifier</p> <p>18</p> <p>Raman Amplifier</p> <p>Multistage Amplifier Counter propagating pumpJanuary 8, 2008 Y. Lin: Raman Amplifier 19</p> <p>EDFA+Raman</p> <p>Combined Raman and EDFA transmission Experiment: DWDM (Lucent)January 8, 2008 Y. Lin: Raman Amplifier 20</p> <p>EDFA+Raman</p> <p>Wide band amplification is possible by dividing into subbands (Lucent)January 8, 2008 Y. Lin: Raman Amplifier 21</p> <p>EDFA+Raman</p> <p>Gain-flattened EDFA+Raman ( Japan)January 8, 2008 Y. Lin: Raman Amplifier 22</p> <p>EDFA+Raman</p> <p>Gain-flattened EDFA+Raman ( Japan)January 8, 2008 Y. Lin: Raman Amplifier 23</p> <p>EDFA+Raman</p> <p>Gain-flattened EDFA+Raman (Japan)January 8, 2008 Y. Lin: Raman Amplifier 24</p> <p>ConclusionsHigh-power laser sources are available by Raman process itself. 200 to 400 nm Bandwidth Amplifiers are possible Raman, EDFA combination Flat gain for WDM New fiber lasers and gratings make it practical System with Terabits of capacity are possible</p> <p>January 8, 2008</p> <p>Y. Lin: Raman Amplifier</p> <p>25</p> <p>ReferencesOptical Fiber Telecommunications, Ivan P. Kaminow (1997) Optical Amplifier and Their Application, Douglas M. Baney (1998) Waveguide Optoelectronics, J. H. March (1990)</p> <p>January 8, 2008</p> <p>Y. Lin: Raman Amplifier</p> <p>26</p>

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