A cost-effective and rugged actively mode-locked erbium-doped fiber laser operated at GHz repetition rate is demonstrated with the use of a Gunn oscillator as the RF source for driving the optical modulator. The high power from the Gunn oscillator eliminates the need of an RF driver. The output of the laser in the time domain is processed numerically to predict its modal characteristics in the spectral domain. Experimental results regarding the evaluation of the Gunn oscillator for its suitability in active mode-locking, tunable operation of the laser in the C-band using a band pass filter as well as the results on the stability of the laser output in the time and frequency domain are presented.