Partial parabolic amplification in rare-earth-doped optical fiber

TL;DR

This paper introduces the concept of partial parabolic amplification in rare-earth-doped optical fibers, achieving ultrashort 50-fs pulses with high peak power, and discusses its potential for scalable energy applications.

Contribution

It identifies a new amplification regime, partial parabolic amplification, and demonstrates its effectiveness in producing high-peak-power ultrashort pulses.

Findings

Achieved 50-fs, 2.2-uJ pulses with a 25-um-core Yb fiber amplifier.

Partial parabolic amplification yields higher peak power than other regimes.

Practical energy scaling beyond 10 uJ and 200 MW is feasible with larger mode area fibers.

Abstract

Nonlinear amplification is a powerful technique for generating ultrashort laser pulses with high peak power in fiber systems. However, the diversity of nonlinear amplification approaches and their inherent complexities present significant challenges to achieving a unified understanding and further scaling of peak power and pulse energy while preserving ultrashort durations. Here, we report the results of a systematic optimization with respect to seed pulse duration that elucidates the dynamics of nonlinear amplification and allows identification of distinct propagation regimes. As part of this analysis, we identify a new regime, termed partial parabolic amplification, which achieves 50-fs pulse duration and yields higher peak power than any other nonlinear amplification regime. An initial experimental demonstration of partial parabolic amplification produces 50-fs and 2.2-uJ pulses with a 25-um-core Yb fiber amplifier, corresponding to a 30-MW peak power. In contrast to other nonlinear amplification techniques, practical energy scaling beyond 10 uJ and 200 MW should be achievable with available gain fibers with larger mode areas, which would fill a gap in existing fiber laser capabilities that would directly impact material processing, nonlinear bio-imaging, and other applications.