Dissipative soliton (DS) is demonstrated in a large anomalous dispersion ytterbium-doped fiber laser. A chirped fiber Bragg grating is implemented into a figure-of-9 cavity to provide a large anomalous dispersion. A self-starting and stable DS operation is achieved with 3.5 nJ pulse energy and 12.9 ps pulse duration under a 26.4 MHz repetition rate. Numerical simulations reveal that the DSs presented here experience strong temporal, spectral, and chirp breathing in the cavity. Thanks to the characteristic chirp breathing, the output DS pulses can maintain a narrow spectral bandwidth of 0.17 nm. We believe that the laser design presented here has a lot of potential and could be an outstanding ultrafast seed laser solution for industrial applications including micromachining and hard-brittle material processing.
Nonlinear optical gain modulation (NOGM) is a method to generate high performance ultrafast pulses with wavelength versatility. Here we demonstrate coherent femtosecond Raman pulse generation through cascaded NOGM process experimentally. Two single-frequency seed lasers (1121 and 1178 nm) are gain-modulated by 117 nJ 1064 nm picosecond pulses in a Raman fiber amplifier. Second-order (1178 nm) Stokes pulses are generated, which have a pulse energy of 76 nJ (corresponding to an optical conversion efficiency of 65%) with a pulse duration of 621 fs (after compression). Dynamic evolution of both pump and cascaded Stokes pulses within the Raman amplifier are investigated by numerical simulations. The influences of pump pulse duration and energy are studied in detail numerically. Moreover, the simulations reveal that NOGM pulses with higher energy and shorter pulse duration could be obtained by limiting the impact of walk-off effect between pump and Raman pulses. This approach can offer a high energy and wavelength-agile ultrafast source for various applications such as optical metrology and biomedical imagining.
Many approaches have been explored to generate ultrafast lasers including mode locking, microresonators, electro‐optic modulation, and gain‐switched diodes. Despite much progress, it is still challenging to generate high‐performance ultrafast pulses with wavelength versatility in a simple approach. Herein, a new method is proposed and demonstrated to transform a continuous‐wave (CW) single‐frequency laser into femtosecond‐scale pulses by nonlinear optical gain modulation in a fiber Raman amplifier. The proof‐of‐principle setup generates a stable and highly coherent laser at 1120 nm with a pulse energy of 25.7 nJ, a pulse width of 436 fs, and an optical efficiency of 69.4% by 14 ps gain modulation. Numerical simulation shows that pulse energy scaling to micro‐Joule level is feasible by increasing pump energy. By cascading the conversion process, high‐energy, femtosecond‐scale pulses can be produced over a wide spectral range.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.