Passively mode-locked laser at 1μm region based on tungsten trioxide (WO3) saturable absorber

Abstract Stable and efficient mode-locked operation at 1065 nm was demonstrated using tungsten trioxide (WO3) thin film as a saturable absorber (SA). The WO3 thin film composite was prepared by a low cost and simple method and it has a modulation depth of 20 %. As the SA film was inserted into a Ytterbium-doped fiber laser (YDFL) cavity. The mode-locked laser operated in normal dispersion regime and generated pulses at 1065 nm with 3-dB bandwidth of 1 nm. The YDFL operated at fixed repetition rate of 10 MHz with pulse width of 1.67 ps. The maximum average output power of 21.64 mW and pulse energy of 2.16 nJ were recorded at a pump power of 162 mW.