RESUMEN
We introduce a fully-integrated two-color sub-nanosecond fiber laser system that incorporates a backward-pumped polarization-maintaining (PM) Raman phosphosilicate fiber amplifier (RFA) followed by two fully-integrated fiber-coupled second harmonic generator (SHG) modules. The RFA is pumped by a continuous-wave (CW) Yb laser operating at 1116â nm. The pulsed signals are generated by gain-switched distributed feedback (DFB) laser diodes at 1178â nm and 1310â nm, respectively. The output pulsed DFB signals are independently or simultaneously amplified in the RFA. This amplification is achieved using both the broad SiO2 (â¼13.2 THz) and relatively narrow P2O5 (39.9 THz) Stokes shifts. The laser system produces sub-nanosecond pulses at 589 and 655â nm, featuring repetition rates ranging from 40 to 100â MHz and an average power of up to 3 W (limited by the SHG crystal damage threshold) at each wavelength. The diffraction-limited output beams maintain an M2 value of < 1.05 across the entire range of output powers and repetition rates for both wavelengths.