We report on the first experimental observation of an influence of noise in a pumping diode laser on the appearance of self-induced modulation and self-pulsing in an all-fiber Erbium laser. The diode laser amplitude noise, being a superposition of spectral components, with some of which to match the resonant frequency of relaxation oscillations in the Erbium fiber laser at the pump rate fixed, acts as a disturbing force, being a source of the modulation effects. This disturbance causes the relaxation oscillations of the Erbium fiber laser to become non-dumped and appears as self-modulation and even self-pulsing of the laser output power. (C) 2004 Optical Society of America.