I have been using the universal fiber module to simulate bidirectional transmission of multiple wavelengths in order to design a fiber optic parametric amplifier. But, the input pump powers into the fiber module is limited to just 1mW and below. When I increase the pump power, there pops up a iteration error or sometimes the simulation runs without error and doesn't give any output with a very long runtime. Since online material on VPI is limited unlike the case of OptiSystem, it would be great if i get a suggestion on how this can be corrected.