Overview of Evolution:
Soliton in a cavity-averaged sense. Pulse stretches and compresses temporally twice per roundtrip as it passes through each sign of dispersion, reducing the nonlinearity per roundtrip and permitting increased energy.
Different signs of dispersion in different sections of the cavity (aka a dispersion map). Net cavity dispersions ranging from anomalous to slightly normal are possible, although the shortest pulses are achieved near zero net dispersion as per the cavity-averaged soliton area theorem. The output coupler can be placed anywhere, resulting in different signs and magnitudes of chirp in the output.
Temporal breathing reduces the roundtrip nonlinearity compared to a static solution of the same energy, allowing more energetic pulses than a comparable soliton laser. The dispersion map suppresses sideband generation and resonant instabilities. Output pulses may be somewhat up- or down-chirped, depending on the placement of the output coupler, but may be dechirped to <100 fs outside the cavity with energies of ~2 nJ.
1. M. H. Ober, M. Hofer, and M. E. Fermann. “42-fs pulse generation from a mode-locked fiber laser started with a moving mirror.” Optics Letters 18, 5 (1993).
2. K. Tamura, E. P. Ippen, H. A. Haus, and L. E. Nelson. “77-fs pulse generation from a stretched-pulse mode-locked all-fiber ring laser.” Optics Letters 18, 13 (1993).
3. K. Tamura, L. E. Nelson, H. A. Haus, and E. P. Ippen. “Soliton versus nonsoliton operation of fiber ring lasers.” Applied Physics Letters 64, 149 (1994).
4. L. E. Nelson, S. B. Fleischer, G. Lenz, and E. P. Ippen. “Efficient frequency doubling of a femtosecond fiber laser.” Optics Letters 21, 21 (1996).
Animation credit: Walter Fu.