Read me file: University of Southampton – ORC – Huaiqin Lin – hl3g15@soton.ac.uk The excel file contains experimental data for the paper. In particular: Fig. 2. Laser output power versus launched pump power. Fig. 3. Optical spectrum at 656 W output, resolution: 1 nm. Fig. 4(a). One transient oscillation of the observed self-pulses. Inset: The temporal trace of an individual self-pulse. Fig. 4(b). Occasional relatively weak self-pulses from the Er-doped fiber laser at an output power of 656 W. Fig. 5. Measured beam radius of the output signal in the horizontal and vertical beam axes at maximum output power. Date of data collection: from February 2017 - November 2017 Information about geographic location of data collection: University of Southampton, U.K. Date that the file was created: November 2017