Fig. 1. (a) Photograph and (b) Raman spectrum of a GO paper sample.

Fig. 2. SEM images of (a) GO paper surface with a 1 μm scale bar and (b) cross section with a 200 nm scale bar.

Fig. 3. Experimental setup of an Er-doped fiber laser.

Fig. 4. The FWHM optical spectra comparison for Er-doped fiber laser with up to 4 layers of GO paper as a SA.

Fig. 5. Autocorrelation traces of output pulses from Er-doped fiber laser with up to 4 layers of GO paper as a SA.

Fig. 6. Measured RF spectrum centered at a fundamental repetition frequency of 37.2 MHz and the spectrum measured with full available bandwidth (inset).

Fig. 7. Nonlinear transmission curve of GO paper SA. Inset: linear transmission spectra of GO-paper-based SAs made of one to four layers of GO paper.

Fig. 8. Experimental setup of a Tm-doped fiber laser.

Fig. 9. Optical spectrum of the Tm-doped fiber laser.

Fig. 10. (a) Autocorrelation trace of a 1.36 ps pulse generated in the Tm-doped fiber laser, (b) the linear transmission spectrum, (c) the fundamental repetition rate and RF spectrum in a 3 GHz span (inset) and (d) oscilloscope trace of output pulses.