We demonstrate the generation of mode-locked pulses in an erbium-doped fiber laser (EDFL) by using a new manganese-doped cadmium selenide quantum-dots-based saturable absorber. The laser produces a soliton pulse train operating at 1561.1 nm with a repetition rate of 1 MHz, as the pump power is varied from 113 to 250 mW. At the maximum pump power, we obtain the pulse duration of 459 ns with a signal-to-noise ratio of 50 dB.