Supercontinuum generation, four-wave mixing, and fission of higher-order solitons in photonic-crystal fibers

Abstract

The nonlinear propagation of femtosecond pulses in photonic-crystal fibers is investigated theoretically without the use of the slowly varying envelope approximation. Low-intensity supercontinuum generation caused by fission of higher-order solitons into red-shifted fundamental solitons and blue-shifted nonsolitonic radiation is studied in a large range of fiber and pulse parameters. It is shown that phase matching of degenerate four-wave mixing can be achieved in an extremely broad frequency range from the IR to the UV. Spontaneous generation of new frequency components and parametric amplification by four-wave mixing as well as its possible overlap with soliton fission are studied in detail.