N. Minkovski et al., GENERATION OF A WIDE DISCRETE VISIBLE SPECTRUM IN A FREQUENCY-DOUBLING OPTICAL-FIBER, Applied physics. B, Lasers and optics, 63(1), 1996, pp. 20-23
We describe some special features of frequency doubling in a Ge-doped
SiO2 optical fiber. The generation of a multi-frequency visible spectr
um in a single short fiber pumped with 1.06 mu m radiation is demonstr
ated. This effect is the result of an interplay between the processes
of frequency doubling and third-order nonlinear frequency mixing. Most
of the new components coincide with the characteristic stimulated fou
r-wave-mixing spectrum of the fiber, although the power of the interna
lly generated 0.532 mu m pump was more than an order of magnitude belo
w the respective thresholds.