We report on the generation of a stable multiwavelength Q-switched erbium-doped fiber laser based on tungsten oxide nanoparticles (WO3 NPs) combined with an intracavity comb filter for the first time, to the best of our knowledge. The prepared WO3-PVA thin film has a modulation depth and saturable intensity of 20% and 100 MW/cm(2), respectively. A spectrum of up to 15 peaks with a channel spacing of 0.48 nm has been obtained. In the Q-switching regime, a minimum pulse width of 4.24 mu s and a maximum repetition rate of 52.49 kHz were achieved at a maximum pump power of 300 mW. The dual effect of WO3 NPs in saturable absorption and high optical nonlinearity has induced pulsed and four-wave mixing effects. Therefore, the intrinsic advantages of WO3 nanomaterial provide a promising source for the realization of a stable multiwavelength fiber laser. (c) 2019 Optical Society of America
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