Fiber optical parametric amplifiers (OPAs) are based on the third-order nonlinear susceptibility of glass
fibers. If two strong pumps and a weak signal are fed into a fiber, an idler is generated. Signal and idler
can grow together if pump power is high enough, and phase matching occurs. Until recently,
impressive performance of fiber OPAs has been demonstrated in different respects. However, secondorder
effects should be addressed before OPAs can be utilized in practical applications. Here we report
some of these effects, either exploiting them as in the parametric processor such as optical logic gates,
inverted and non-inverted wavelength converter, and ultra-wideband monocycle and doublet pulses
generator, or suppressing them as in the optical amplifier for WDM systems.