Balancing gain narrowing with self phase modulation: 100-fs, 800-nJ from an all-fiber-integrated Yb amplifier

Source Title
2013 Conference on Lasers & Electro-Optics Europe & International Quantum Electronics Conference CLEO EUROPE/IQEC
Print ISSN
Electronic ISSN
Conference Paper
Journal Title
Journal ISSN
Volume Title

There is much progress in Yb-fiber oscillator-amplifier systems, which enable generation of high-repetition-rate, microjoule energies and sub-picosecond pulse widths [1,2]. Given the extremely large total gain factors to reach microjoules starting from nanojoules, which is often in the range of 40-60 dB, due to losses, and the impact of mismatched high-order dispersion as temporal stretching and compression of pulses by large factors (30-40 dB) need to be employed. As a result of these challenges, most of the Yb-fiber amplifiers have resulted in pulse durations of several 100 fs or longer. While pulse durations in this range are suited for some applications, there are many cases where 100-fs or shorter pulses in microjoule range are required. Gain narrowing can be effectively countered by self-phase modulation (SPM) [3] by limiting amplification factor in each stage of amplification and through careful optimization of SPM and inversion level along the gain fiber. The conceptual template is readily present in the evolution of the pulse inside the oscillator cavity, where gain factors are often in the 10-50 range per roundtrip. To the extend that the B-integral and the gain distribution along the amplifier can be kept identical to the oscillator by proper scaling of the chirped pulse width and fiber mode area, the original oscillator can be preserved in arbitrary number of amplification stages. Here, we demonstrate a highly fiber-integrated master-oscillator power-amplifier (MOPA) system, from which - 1 μJ pulses are extracted and externally compressed to 100 fs by arranging amplification in each stage as close as possible to the intra-cavity evolution. To our knowledge, these results are the shortest demonstrated from all-fiber-integrated amplifier at the microjoule level. © 2013 IEEE.

Other identifiers
Book Title
Electron optics, Fiber amplifiers, Fibers, Integrated optics, Modulation, Power amplifiers, Quantum electronics, Self phase modulation, Ytterbium, Amplification factors, Arbitrary number, Compression of pulse, Gain distribution, High repetition rate, High-order dispersion, Inversion levels, Oscillator amplifier, Amplification
Published Version (Please cite this version)