Bidirectional mode-locked all-normal dispersion fiber laser
Bowen Li, Jian Xing, Dohyeon Kwon, Yijun Xie, Neeraj Prakash, Jungwon Kim, Shu‐Wei Huang
Abstract
The bidirectional mode-locked oscillator is an emerging light source architecture suitable for dual-comb applications. Therein, bidirectional mode-locked fiber lasers (MLFLs) are particularly promising for their cost effectiveness, system compactness, and environmental robustness. However, the pulse energy has been limited to tens of picojoules, restricting practical dual-comb applications, especially in the nonlinear regime. In this paper, we break the pulse energy limit by devising the first bidirectional all-normal dispersion MLFL with an artificial saturable absorber (ASA). Bidirectional dissipative solitons are generated with <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo>></mml:mo> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>5</mml:mn> </mml:mrow> </mml:mrow> </mml:math> -THz bandwidths and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo>></mml:mo> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>1</mml:mn> </mml:mrow> </mml:mrow> </mml:math> -nJ pulse energies. Free-running laser performance is extensively characterized, and the physical mechanism for bidirectional ASA mode-locking is studied. Last but not least, a proof-of-concept dual-comb spectroscopy measurement is demonstrated. Our work paves the way for a new class of bidirectional MLFLs benefiting dual-comb applications in both linear and nonlinear regimes.