  We demonstrate the first multimode fiber interference-based filtering in an
all-fiber spatiotemporally mode-locked laser. The oscillator generates
dissipative soliton pulses at 1036 nm with 12 mW average power, 6.24 ps
duration and 24.3 MHz repetition rate. The reported pulse energy (0.5 nJ)
represents ~4 times improvement over the previously reported single-mode
all-normal dispersion mode-locked lasers with multimode interference-based
filtering. Numerical simulations are performed to reveal cavity and
spatiotemporal mode-locking dynamics. The proposed oscillator presents an
alternative approach to achieve spatiotemporal mode-locking with an all-fiber
design that can be fabricated simply.
