Demonstration of nondegenerate spectrum reversal in optical-frequency regime.

This Letter reports theoretical and experimental studies of spectrum reversal with tunable wavelength offset in the optical-frequency regime-two widely separated spectral sidebands can always behave as mirror images of one another with respect to the center frequency of the controlling pump pulse. We call this interesting physical phenomenon "spectral mirror imaging."

Cross-phase-modulation-induced spectral effects in high-efficiency picosecond fiber optical parametric oscillators.

We explore the spectral effects due to cross-phase modulation and walk-off in picosecond fiber optical parametric oscillators. The output spectrum exhibits pump-power-dependent broadening, which can be quite asymmetric associated with a redshift or a blueshift depending on pump synchronization. By slightly increasing the cavity length, one obtains a blueshifted spectrum and a conversion efficiency as high as 15%.

Fiber optical parametric oscillator for sub-50 fs pulse generation: optimization of fiber length.

We demonstrate generation of 48fs pulses with linear chirp using a short (27mm) fiber optical parametric oscillator (FOPO), which is synchronously pumped by a mode-locked ytterbium-doped fiber laser. We also study the pulse quality for both the short- and long-wavelength operation where the fiber length inside of the oscillator varies from 17 to 61mm. The optimal pulse duration is observed only in the short-wavelength operation. Furthermore, we model the FOPO system as a single-pass parametric amplifier including dispersive pulse broadening and walk-off between the pump and output. The optimal condition arises from the minimization of the walk-off and dispersion. When walk-off is large, the parametric amplification process is most efficient over some reduced effective fiber length, leading to an upper limit in the amount of the observed pulse broadening.

Microstructure fiber optical parametric oscillator with femtosecond output in the 1200 to 1350 nm wavelength range.

We describe an ultrafast fiber optical parametric oscillator operating in the 1210 nm to 1340 nm wavelength range. The system consists of a microstructure fiber placed in a Fabry-Perot cavity which is optically pumped with 1030-nm light from an Ytterbium mode-locked fiber laser. The output wavelength is tunable over a 130-nm span by adjusting the position of one cavity mirror. SHG FROG measurements reveal that the output pulse quality varies as a function of pump power and wavelength. Ultrafast sources operating in this range are particularly instrumental for deep-tissue nonlinear biophotonics applications.