Tunable femtosecond dispersive waves generation in PCF

Tunable femtosecond optical pulses are widely needed in various applications. Recently, the largest tuning range is generally achieved by adding the desired filter after white light generation, which causes a complicated system and a low efficiency. Due to the most recent development of photonic crystal fibers (PCF), the optical dispersion behavior can be modulated a lot. With ultrashort pulses propagating along the fiber, this modulated dispersion can resolve generation of new wavelengths. We will show that more efficient tunibility can be achieved by simply using a femtosecond oscillator and a piece of PCF, and the tuning range will cover more than octave spectrum. The autocorrelation shows that with a femtosecond pulse propagating in a reasonable short PCF, the shifted pulses are femtosecond pulses as well. This phenomenon may expand applications in the fields that the laser wavelengths are not easily obtained.