Self mode locked OPSL: role of high-order modes in starting self-mode-locked operation

Abstract

We have experimentally explored the influence of high-order modes on the temporal dynamic of optically pumped semiconductor laser with two different pump-to-mode size ratios omega(p)/omega(l). With a large pump-to-mode size ratio of 1.45, the output beam profile contributed of TEM0,0 mode and few high-order TEMn,m modes were observed and self-mode-locked operation can be started simultaneously. At an incident pump power of 20W, the laser emits 6 W of average output power with 1.17 ps pulse duration at a repetition rate of 1.2GHz.