Analyses of mode-hopping phenomena in an AlGaAs laser

Intensity fluctuations of the longitudinal modes of a 0.8 μm AlGaAs laser were precisely measured during the occurrence of hopping between two modes. It was found from this result that mode hopping follows the stochastics of a Poisson process. The frequency of mode hopping was measured as (Hz). where is the injection current normalized to its threshold value. Results of analog computer simulations showed that spontaneous emission worked as a triggering force for mode hopping. Results of the analysis based on the Fokker-Planck equation were compared to the experimental results, from which the root-mean-square value of the fluctuating electric field of spontaneous emission was estimated as (V/m) (V/m). It is concluded that an effective reduction of mode hopping is achieved if the laser is operated at a higher bias or if the coupling constant between the two modes is increased.