"Fiber-based Femtosecond Modelocked Lasers and Frequency Combs at GHz Repetition Rates"

Dr. David Chao, Massachusetts Institute of Technology

October 26th (Friday), 11:00am
Harold Frank Hall (HFH), Room 4164

Tremendous advances in recent years to the optical frequency comb, particularly frequency combs deriving from solid-state and fiber architectures, have enabled a host of important new applications to emerge – applications which include optical arbitrary waveform generation (OAWG), high-speed photonic analog-to-digital conversion (EPIC), advanced space exploration (Astro-Comb) as well as precision spectroscopy and optical clocks. Fiber-based frequency combs have increasingly become attractive alternatives to solid-state systems due to their compact size and robust operation, and have recently demonstrated performance comparable to their more traditional counterparts. One area for improvement, however, is in the repetition rate of such systems, as Erbium-doped fiber frequency combs currently only operate with repetition rates at or below 300MHz, while solid-state frequency combs have been demonstrated up to 10GHz. This talk will address the issues limiting the repetition rates of fiber-based femtosecond modelocked lasers and frequency combs, and report on the development of a 1-GHz Erbium fiber laser frequency comb. Nanojoule femtosecond pulses are produced at a GHz repetition rate and used to generate over an octave of supercontinuum spanning 1-2.4[microns]. Subsequent carrier-envelope phase detection and stabilization is achieved via f-2f interferometry, yielding the first completely self-referenced octave-spanning optical frequency comb of its kind. Future work, including various chip-based approaches to frequency combs, will also be discussed.

About Dr. David Chao:

David Chao received his B.S. degree in electrical engineering from Cornell University (2003), and his S.M. and Ph.D. degrees in electrical engineering from MIT (2005 and 2012). His current research focuses on ultra fast nonlinear techniques for femtosecond pulse generation, amplification, and compression, with a particular emphasis towards low-noise optical frequency combs. His interests are in the integration of these technologies from fiber to chip. Dr. Chao is a member of the Optical Society of America and IEEE.

Hosted by: Professor John Bowers, Electrical and Computer Engineering