Applied Physics Seminar

Nonlinear wave mixing in optical microresonators offers a route to chip-level optical frequency combs.  The properties of the Kerr combs generated depend crucially on the interaction between nonlinearity and dispersion.   Much of the research in this field focuses on anomalous dispersion microresonators, leading to combs comprising bright soliton pulses.  In this talk I discuss a different approach involving normal dispersion microresonators.  After a general introduction to Kerr combs, I first describe the role of mode interactions in initiation of combs in the normal dispersion regime. I then discuss generation and characterization of combs comprising mode-locked dark pulses.  These dark pulses show some resemblance to dark solitons that can propagate in optical fibers but also have distinct differences.  Finally, I present recent results demonstrating efficient power conversion (>30%) into dark pulse combs, a value substantially higher than has typically been observed in Kerr comb generation.

More about the speaker:  Andrew Weiner, the Scifres Family Distinguished Professor of Electrical and Computer Engineering at Purdue University, is best known for pioneering work on programmable femtosecond pulse shaping and ultrafast signal processing.  Weiner is a member of the National Academy of Engineering and recipient of numerous awards, including the OSA Wood Prize and the IEEE Photonics Society Quantum Electronics Award.  He is author of the textbook Ultrafast Optics and serves as Editor-in-Chief of Optics Express.