Highly Efficient Anti-Stokes Signal Conversion by Pumping in the Normal and Anomalous Dispersion Regions in the Fundamental Mode of Photonic Crystal Fiber

By pumping near the zero dispersion wavelength, the highly efficient anti-Stokes signal conversions of the femtosecond pulses in the fundamental mode of photonic crystal fiber (PCF) with the zero dispersion wavelength of 848 nm have been achieved within the wavelength range of 644 to 543 nm. When the pump works at 820 nm, 830 nm and 840 nm with the average power of 500 mW, the power ratios of the anti-Stokes signals at 594 nm, 581 nm, and 543 nm and the residual pump components are 9.8:1, 17.6:1, and 22.6:1, and the corresponding conversion efficiency η can be up to 33%, 39%, and 46%. When the pump works at 860 nm with the same power, the power ratio of anti-Stokes signals at 553 nm and the residual pump components is 19.4:1 with η of 43%. In the experiment, because of low output powers of the trivial and residual pump components and high depletion of Stokes components, the output anti-Stokes signal spectra appear much clearer, and the optical beams of signals are with good qualities. The influences of pump power and wavelength interval between the working wavelength and zero dispersion wavelength of PCF on the signal conversion are also demonstrated.