Research on highly nonlinear photonic bandgap fibers

A new type of highly nonlinear photonic bandgap fiber with modified honeycomb lattice is brought forward. Based on full-vector plane-wave method, the structure of bandgaps and the distributions of fundamental mode field are analyzed. Then its nonlinear coefficient is calculated, and the effect of each structural pa- rameter on the nonlinear coefficient is discussed. At last, considering many factors synthetically, we make some optimization design of the structural parameters. It can be concluded that this new type of photonic bandgap fiber can gain the nonlinear coefficient of 30 W^-1 km^-1.