| Abstract: | The carboxyl-functionalized graphene oxide(GO-COOH) is a kind of unique two-dimensional(2 D) material and possesses excellent nonlinear saturable absorption property and high water-solubility. In this paper, we prepare saturable absorber(SA) device by depositing GO-COOH nanosheets aqueous solution on a D-shaped fiber. The modulation depth(MD) and saturable intensity of the SA are measured to be 9.6% and 19 MW/cm~2, respectively. By inserting the SA into the erbium-doped fiber(EDF) laser, a passively mode-locked EDF laser has been achieved with the spectrum center wavelength of 1562.76 nm. The pulse duration, repetition rate, and the signal-to-noise ratio(SNR) are 500 fs, 14.79 MHz, and 80 dB,respectively. The maximum average output power is measured to be 3.85 mW. These results indicate that the GO-COOH nanosheets SA can be used as a promising mode locker for the generation of ultrashort pulses. |
