Performance of passively Q-switched ring erbium-doped fiber laser using a multiwalled carbon nanotubes polyethylene oxide (PEO) polymer composite-based saturable absorber

The aim of this article is to report the fabrication and characterization of dispersed multiwalled carbon nanotubes (MWCNTs) polymer composites and use them as passive SAs in Q-switched Erbium-doped fiber (EDF) for ultrafast laser generation at 1.5-mu m region. CNT polymer composites were fabricated into thin films by homogenizing different concentrations (1.8, 4.8, and 10.1 wt. ) of MWCNTs with host polymers polyethylene oxide. The fabricated thin film was then deposited between two fiber connectors as passive SA and incorporated into fiber laser's ring oscillator. The EDFL exhibited a central wavelength of 1560.5 nm when pump power is fixed at 42 mW. The Q-switching operation starts at the lowest threshold of 39.3 mW for all the three different SA concentrations. For 1.8 wt. MWCNTs concentration, the pulse repetition rate of the Q-switched EDFL is started from 35.6 kHz, while for 4.8 wt. and 10.1 wt. , the pulse repetition rate started at 78.5 and 66.1 kHz, respectively. At the MWCNTs concentration of 1.8 wt. , the pulse energy of the Q-switched EDFL increases from 7.9 to 24.7 nJ as the pump power increases from 39.3 to 58.8 mW. (c) 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1897-1901, 201