Erbium Fiber Laser with 340 nJ, 63 fs Pulses from Standard Single Mode Telecom Fiber

Femtosecond fiber lasers in the anomalous dispersion regime, such as Er and Tm lasers with wavelengths longer than 1.3 μm, rely on nonlinearity for spectral broadening and pulse compression. At high intensities, the nonlinearity becomes uncontrolled, limiting maximum output. For an all-fiber Er laser, the record pulse energy is 34 nJ, in 12/130, likely multimode, fiber [1] . Divided pulse amplification has increased that to 60 nJ [2] by reducing the peak power in the fiber. Rather than alter the system to reduce peak power, our approach is to use a simple phase shaping method to delay pulse collapse, enabling increased pulse energy without a comparable increase in spectral broadening and temporal compression.