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Ultrafast Nonlinear Dynamics of Quantum Dot Semiconductor Optical Amplifiers. Aaron J. Zilkie PhD Candidate. Supervisors: Peter W. E. Smith J. Stewart Aitchison. Connections 2006. In collaboration with: National Research Council of Canada, Ottawa, ON. Outline.
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Ultrafast Nonlinear Dynamics of Quantum Dot Semiconductor Optical Amplifiers Aaron J. Zilkie PhD Candidate Supervisors: Peter W. E. Smith J. Stewart Aitchison Connections 2006 In collaboration with: National Research Council of Canada, Ottawa, ON
Outline • Introduction and Motivation 2) Experimental Setup • Heterodyne pump-probe lab setup 3) Ultrafast Dynamics • Ultrafast Gain recovery • Additional Ultrafast Nonlinearities 4) Conclusions Friday, June 9 U of T Connections 2006
+ SEM Cross-section p n 500 nm - Introduction Quantum Dot Semiconductor Optical Amplifiers (QD SOA) • “Single pass laser” – light enters, experiences gain via stimulated emission as it passes through • QD SOAs predicted to have 10-100 X faster recovery times than others • NRC QDs Novel: First to work at 1.55 μm telecom wavelengths Friday, June 9 U of T Connections 2006
Motivation All Optical Signal Processing Nonlinear phase change balanced balanced Supression • SOA used as nonlinear switching element • Control pulses induce phase change light can switch light! unbalanced SOA ultrafast dynamics critically influence switching window Our Work: Measure the ultrafast dynamics of novel QD SOAs Friday, June 9 U of T Connections 2006
Heterodyne Pump-probe Setup (phase) (amplitude) Friday, June 9 U of T Connections 2006
Heterodyne Pump-probe Setup Friday, June 9 U of T Connections 2006
Heterodyne Pump-probe Setup Friday, June 9 U of T Connections 2006
Heterodyne Pump-probe Setup Friday, June 9 U of T Connections 2006
Heterodyne Pump-probe Setup Friday, June 9 U of T Connections 2006
Heterodyne Pump-probe Setup Friday, June 9 U of T Connections 2006
pump probe reference (amplitude) Δt t Heterodyne Pump-probe Setup Friday, June 9 U of T Connections 2006
pump pump pump pump probe probe reference reference probe reference (amplitude) (amplitude) (amplitude) Δt Δt Δt t t t probe reference reference (amplitude) Δt t Heterodyne Pump-probe Setup Michelson Interferometer Friday, June 9 U of T Connections 2006
pump pump pump pump probe probe reference reference probe reference (amplitude) (amplitude) (amplitude) Δt Δt Δt t t t probe reference reference (amplitude) Δt t Heterodyne Pump-probe Setup Michelson Interferometer Friday, June 9 U of T Connections 2006
pump probe reference (amplitude) Δt t Heterodyne Pump-probe Setup Michelson Interferometer 1.5 MHz beat (phase) (amplitude) Friday, June 9 U of T Connections 2006
τcr ≈ 400 ps Ultrafast Gain Recovery Gain recovery Absoptrion recovery τgr ≈ 15 ps • Gain recovery time dictates switching rate • Recovery time is 15 ps for high bias currents 100 GHz switching rate (faster than possible with electronics) Friday, June 9 U of T Connections 2006
Other Ultrafast Dynamics Additional ultrafast (~ 1 ps) nonlinear dynamics Friday, June 9 U of T Connections 2006
TPA Other Ultrafast Dynamics Additional ultrafast (~ 1 ps) nonlinear dynamics • Two-Photon Absorption (TPA) • Carrier Heating (CH) • Spectral Hole Burning (SHB) Friday, June 9 U of T Connections 2006
Conclusions First characterization of dynamics of 1.55 µm QDSOA • Heterodyne pump-probe characterization with 150 fs resolution • QD SOAs used as nonlinear elements in All-Optical Signal Processing • Fast 15 ps gain recovery • promising for ultrafast signal processing to beat electronics limit ( > 40 GHz ) • Faster than conventional SOAs (50 – 1000 ps) • Slow absorption dynamics confirms high quantum confinement • Ultrafast ~1 ps dynamics due to SHB and CH • Provides deeper understanding of QD Physics Friday, June 9 U of T Connections 2006
References • A. J. Zilkie, J. Meier, P. W. E. Smith, M. Mojahedi, J. S. Aitchison, P. J. Poole, C. Nì. Allen, P. Barrios, and D. Poitras, Appl. Phys Lett., in submission • A. J. Zilkie, J. Meier, P. W. E. Smith, M. Mojahedi, J. S. Aitchison, P. J. Poole, C. Nì. Allen, P. Barrios, and D. Poitras, CMJJ5, CLEO 2006 • J. Meier, A. J. Zilkie, M. Mojahedi, J. S. Aitchison, R. H. Wang, T. J. Rotter, C. Yang, A. Stintz, K. J. Malloy, CThGG4, CLEO 2006 • A. J. Zilkie, J. Meier, P. W. E. Smith, M. Mojahedi, J. S. Aitchison, P. J. Poole, C. Nì. Allen, P. Barrios, and D. Poitras, Photonic Applications in Nonlinear Optics, Nanophotonics, and Microwave Photonics 5971, 59710G (2005). Oral presentation at SPIE Photonics North September 2005 • B. Leesti, A. J. Zilkie, J. S. Aitchison, M. Mojahedi, R. H. Wang, T. J. Rotter, C. Yang, A. Stintz, and K. J. Malloy (2004) Photonic. Tech. L. 17 (5), 1046-1048 (2005). • B. Leesti, A. J. Zilkie, J. S. Aitchison, M. Mojahedi, P. W. E. Smith, R. H. Wang, T. J. Rotter, C. Yang, A. Stintz, and K. J. Malloy, IEEE LEOS Annual Meeting November 2004, poster presentation by B. Leesti. Friday, June 9 U of T Connections 2006
NSERC CRSNG Acknowledgments Friday, June 9 U of T Connections 2006