Optical supercontinuum generation from nanosecond pump pulses in an irregularly microstructured air-silica optical fiber

An optical supercontinuum was generated by pumping a short length of randomly microstructured air-silica optical fiber with a Q-switched Nd:YAG laser. The use of relatively long pump pulses and a longer pump wavelength are believed to be responsible for an improvement in results relative to similar previous reports. A figure of merit for optical continuum generation is defined, and is shown to be considerably larger in this and other experiments in which stimulated Raman scattering, instead of self-phase modulation, is the primary nonlinear process seeding spectral broadening.