For nearly two decades chirped pulse amplification was the only technique used for high energy and power ultrashort-pulse fiber lasers. However, due to the stretched pulse durations being limited to ~1ns, fiber CPA can extract from a fiber amplifier only approximately 1–5% of the stored energy. Coherent pulse stacking amplification (CPSA) is a new ultrashort pulse amplification technique, based on time-domain coherent pulse combining to extend amplified pulse durations to approximately 100ns, which allows nearly complete extraction of all stored energy from a fiber amplifier. In this talk I will describe the fundamentals of the technique, its operation and performance, as well as experimental demonstration of 10mJ femtosecond pulse generation from a large core fiber amplifier system (based on 85 µm Yb-doped CCC fiber). I will also discuss implications of using this technique for developing multi-TW peak (and multi-kW average) power fiber laser systems based on time-domain and spatial-domain combining.

 

AlmantasGalvanauskas is a professor at the Electrical Engineering and Computer Science Department, University of Michigan, and at the Center for Ultrafast Optical Science (CUOS). His primary research interests are in the field of fiber lasers, high power and ultrafast fiber lasers in particular, with other research interests ranging from nonlinear optics, to high intensity laser-matter interactions, driven secondary-radiation sources, and laser acceleration of charged particles. Dr. A. Galvanauskas’s research experience spans approximately 30 years, and includes a number of high-impact inventions and innovations (such as fiber CPA techniques, engineerable pulse compression using QPM nonlinear materials, use of fiber lasers for efficient EUV and X-ray generation, chirped volume Bragg grating pulse stretchers and compressors, chirally-coupled-core (CCC) fiber structures, Coherent Pulse Stacking Amplification technique, etc.), as well as several world-record breaking fiber-laser performance demonstrations in terms of pulse energy, power and other key characteristics. His early work on fiber CPA had been commercialized by IMRA America, Inc. In 2007 he co-founded a start-up company Arbor Photonics, Inc., which commercialized his invention of CCC fibers, and which was subsequently acquired by nLight, Inc. Dr. A. Galvanauskas is a Fellow of the Optical Society of America.