INTRACAVITY LASER-DIODE-PUMPED AND MODULATED ER3-DOPED FIBER LASERS()

We reported on a pulsed compound Er3+-doped laser that simultaneously uses an intracavity laser diode for optical pumping, gain or phase mod ulation, and as a bandwidth control etalon. We demonstrate a simple me thod to produce high-energy pulses with peak powers up to 100 times th e average power, and with durations on the order of 1 mus using the sy nchronization of relaxation oscillations by drive current modulation o f the intracavity pump laser diode. The forced sustained relaxation os cillations are shown to depend on wavelength, and the frequency lockin g curve exhibits strong asymmetry with hysteresis behavior. Tunable lo cked spiking operation provides an interesting tool for characterizati on of the laser dynamics. We have found that the relaxation oscillatio ns and laser transition behavior of the Er3+-doped fiber laser are som ewhat different in 1.53 and 1.55 mum bands. The substantial finding is that the fiber laser, operating at lambda = 1.53 mum, could be mode l ocked by modulation of drive current of 0.98 mum pump laser diode. FM mode locking was obtained with an output pulse width of almost-equal-t o 400 ps, which was limited by bandwidth of laser diode etalon.