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Dr Stephane Coen

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Associate Professor

Biography

I hold a degree in Civil Engineering (Physics) (1996) and a PhD (1999) from the Université libre de Bruxelles (ULB). My PhD was funded by the Belgian Fund for Scientific Research (FNRS) and supervised by Prof. Marc haelterman. From May 2000 to October 2001, I visited the Physics Department of The University of Auckland as a post-doctoral fellow (still funded by the FNRS) under the supervision of Prof. John D. Harvey, during which I worked on supercontinuum generation in photonic crystal fibres. I came back to ULB (Brussels) in November 2001 to complete my FNRS fellowship. In December 2003, I was appointed Lecturer in the Physics Department of The University of Auckland. I have been promoted to Senior Lecturer in February 2006 and to Associate Professor in 2013.

Research | Current

I am involved with theoretical and experimental studies of fundamental nonlinear optical phenomena.

During my PhD in Brussels, I have focused on the study of the dynamics of passive nonlinear optical fibre resonators, investigating optical bistability, period-doubling instabilities and optical chaos, and several regimes of intracavity modulation instabilities. This has led to the demonstration of a continuous-wave ultrahigh repetition rate laser source based on modulation instability and operating at more than 100GHz. The structural simplicity of passive optical fibre cavities has also been used to investigate more fundamental nonlinear dynamics such as a competition between a dispersive and a convective transport mechanism. This latter aspect has been dramatically illustrated by the experimental demonstration of the inhibition of optical bistability in synchronously pumped nonlinear cavities in presence of a cavity synchronisation mismatch smaller than 1% of the pump pulse width.

For my post-doctoral stay in Auckland, I worked on supercontinuum generation, a process where a single frequency laser beam is converted into a white light continuum containing light spanning two octaves in frequency (ie, a laser rainbow extending from the ultra-violet well into the infra-red). Particular interest has been paid to the study of the various mechanisms underlying the spectral broadening through experiments and numerical simulations. I have also been investigating the coherence and noise properties of these light sources, both under pulsed and continuous-wave pumping conditions. This work led to a review paper published in 2006 in Reviews of Modern Physics.

Supercontinuum generation in fibres being strongly connected to stimulated Raman scattering, I have paid a particular attention to this process. In particular, I have studied the intricate coupling between parametric and Raman interactions, and have investigated mode-locked Raman fibre lasers.

From 2010, I started working again on the dynamics of nonlinear resonators, realizing the first observation of temporal cavity solitons. I went on to develop technologies to fully control these localized structures (excitation, trapping, temporal tweezing, controlled collisions). I later showed how these solitons were underlying the generation of optical frequency combs in Kerr microresonators, and suggested the use of the Lugiato-Lefever equation as a computationally efficient model for these devices. Further experiments in fibres were then performed to illustrate dynamics that could not be observed in microresonators (super cavity solitons, breathing temporal cavity solitons, and spatio-temporal chaos). In recent years, I have been interested in the polarization dynamics of nonlinear resonators, observing dissipative polarization domain walls in particular. Also, I helped in developing widely tunable parametric sources based on microresonators.

Distinctions/Honours

  • 2017 James Cook Fellowship from the The Royal Society of New Zealand (RSNZ) – for 2 years
  • 2016 Hector Medal of The Royal Society of New Zealand (RSNZ)
  • 2015 Elected Fellow of The Optical Society of America (OSA)
    Research Medal of The New Zealand Associate of Scientists (NZAS)
  • 2014 Research Excellence Award of The University of Auckland

Areas of expertise

  • Nonlinear (fibre) optics
  • Nonlinear passive resonators, temporal cavity solitons
  • Microresonator frequency combs
  • Supercontinuum generation

 

Committees/Professional groups/Services

  • Fellow of The Optical Society of America

Selected publications and creative works (Research Outputs)

Identifiers

Contact details

Primary office location

SCIENCE CENTRE 303 - Bldg 303
38 PRINCES ST
AUCKLAND 1010
New Zealand

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