• Tellurene as saturable absorber with optical responses was prepared by LPE method. • Conventional soliton operations and harmonic mode-locked soliton operations are demonstrated by adjusting the polarization state and pump power. • Conventional soliton mode-locked operation with pulse width of 1.41 ps was achieved. • Passively mode-locked operation has high stability. In this study, we investigated the nonlinear absorption properties of palladium diselenide (PdSe 2). We employed PdSe 2 with a saturable intensity of 23.40 MW/cm2 and a modulation depth of 7.39 % as a saturable absorber (SA), which was successfully exploited to attain a stable mode-locked pulse within an Er-doped fiber laser (EDFL). Centered at 1557 nm, the EDFL produced stable pulses when the pulse width was 1.31 ps and the fundamental frequency rate was 12.56 MHz. Single, double, and triple pulses were observed by changing the polarization state of the EDFL. The third, fourth, sixth, tenth and eleventh harmonic mode-locked pulses were obtained by adjusting the pump power as well as the polarization state of the laser cavity. This proved that PdSe 2 was an outstanding SA in the research of ultrafast optical modulators due to its excellent ultra-fast modulation properties. [ABSTRACT FROM AUTHOR]