Some laws governing intracavity second harmonic generation

The spectral mode representation of fields in the resonator is used to calculate temporal and spectral characteristics of pulses from an actively mode-locked laser with intracavity frequency doubling and feedback at the harmonic frequency. The calculation results agree qualitatively with experimental data. It is shown experimentally that phase effects due to mismatch of the waves interacting in a system of coupled resonators are clearly observed only for one of the directions of propagation of the radiation in the resonator.