Longitudinal Mode Competition in Semiconductor Injection Lasers

In transverse-mode stabilized injection lasers, a low frequency intensity noise arises at certain ranges of temperature and bias current, where an oscillation mode jumps to a neighboring mode1); random switching1,2) takes place between these modes and the laser power switches between two distinct levels since output power is different between different modes. There is a general rule in the power change at random switching; a power level PS for a shorter wavelength mode (s-mode) is always higher than a power level P1 for a longer wavelength mode (1-mode).1,2