All-Fiber Picosecond Optical Parametric Oscillator at 933 nm Based on Raman-Assisted XMPI in a Step-Index PM Fiber

Fiber optical parametric amplifier/oscillator (FOPA/FOPO) based on modulation instabilities (MI) gain are now recognized as an important technique to generate coherent light at non-conventional wavelengths outside the emission spectral bands of rare-earth ion doped fiber lasers [1]. In particular, large frequency shift parametric sidebands can be generated when pumping in the normal dispersion regime. Widely tunable MI gain bands may also be achieved when pumping near the zero-dispersion wavelength (ZDW), generally using a photonic crystal fiber (PCF) to shift the ZDW at shorter wavelengths near 1 μm. FOPA systems using a PCF pumped by a mode-locked femtosecond laser have been widely reported in the literature. However, the need for a seed source and a powerful pump makes the system rather complex and prevents it from being fully fiberized due to excessive nonlinear effects and dispersion in passive fibers. In contrast, a FOPO tolerates lower pump peak power, possibly a simplified all-fiber design and generally a better output pulse coherence.