A technique to enhance the stability of optical pulse source has been proposed that employs a specific length of unpumped erbium doped fiber. Two types of pulse sources are used one after the other, one of them is a 10 GHz mode locked laser and the other is a gain switched DFB laser diode with the repetition rate of 2 GHz. A 3-m erbium doped fiber is consolidated outside the cavity of the pulse sources so as to form strong standing waves, resulting into enhanced spatial hole burning effect. As a result, the phase noise of the pulse source is suppressed, whereas the possible undesired changes in the attributes of the pulse source are also nullified because we have designed the setup outside the cavity of the pulse source. Consequently, the timing jitter of the pulse source is reduced significantly.