Residual phase noise and longitudinal mode linewidth measurements of hybridly modelocked external cavity semiconductor diode laser

Summary form only given. We report measurements of residual phase noise knee position and average linewidth of a hybrid modelocked external cavity semiconductor laser. We show that the knee position in our laser linearly increases with cavity frequency and is determined by the average longitudinal mode linewidth. This suggests that, to attain ultra-low jitter modelocked lasers, methods for reducing the longitudinal mode linewidth are needed.