Continuous-Wave and Pulsed Optical Fiber Lasers for Medium Infrared Applications

In this paper, a CW amplifier and a gain-switched Dy³⁺-doped ZBLAN fiber laser, in-band pumped, are modeled. An ad-hoc refined finite difference time method (FDTD) approach has been followed in order to integrate the time-dependent rate equations coupled to the power propagation equations. In-band pumping at 2.8 μm wavelength is employed for simulating the emission of optical pulses at 3 μm wavelength. A time-modulated pump beam allows obtaining a gain switching regime. Preliminary simulation results promise that a pulsed laser, providing stable single-pulse operation at 10 kHz with a peak power close to 8 W and a full wave at half maximum (FWHM) less than 800 ns, for an input pump of 1 W with 30% duty cycle, could be constructed.