Author Affiliations
1École Polytechnique Fédérale de Lausanne, Optics Laboratory, Lausanne, Switzerland2École Polytechnique Fédérale de Lausanne, Laboratory of Applied Photonics Devices, Lausanne, Switzerlandshow less
Fig. 1. Conceptual outline of the multimode fiber cavity and schematic of spatiotemporal mode-locking with beam self-cleaning. (a) Conceptual outline of dispersion-managed cavity design with indicated temporal dynamics. Laser pumping scheme is not presented. (b) Schematic of mode-locking mechanism and experimentally measured output beam profile evolution. CW, continuous wave; ML, mode-locked.
Fig. 2. Pulse evolution in the laser simulations. Pulse duration and spectral bandwidth variation over the cavity. SA, saturable absorber; PC, pulse compressor.
Fig. 3. Numerical investigation of Kerr-induced beam self-cleaning inside GRIN MMF. Propagation of 450 fs pulse with (a) 40 nJ pulse energy and [20%, 30%, 20%, 20%, and 10%] initial coupling condition; (b) 30 nJ pulse energy and [30%, 20%, 20%, 20%, and 10%] initial coupling condition; (c) 20 nJ pulse energy and [30%, 20%, 5%, 25%, and 20%] initial coupling condition; and (d) 20 nJ pulse energy and [35%, 30%, 20%, 10%, and 5%] initial coupling condition.
Fig. 4. (a) Schematic of the laser cavity and beam profile measurements. QWP, quarter-wave plate; HWP, half-wave plate; PBS, polarizing beam splitter; ISO, isolator; and SF, spatial filter. (b) Evolution of near-field output beam profile for decreasing cavity loss from continuous wave to mode-locked operation for 8-nJ output pulse energy.
Fig. 5. Experimental measurements: (a) measured mode-locked spectrum; (b) intensity autocorrelation trace of the chirped pulse; (c) intensity autocorrelation trace of the dechirped pulse, PICASO-reconstructed autocorrelation intensity (dashed), and PICASO-retrieved dechirped pulse shape (inset); and (d) measured beam profile for mode-locked operation and measurement of the beam profile.