Amplitude fluctuations and photon statistics of InGaAsP injection lasers

We experimentally show that the statistical distribution of the light output from an injection laser can be adequately described by the superposition of a coherent electric field and narrow-band Gaussian noise. A technique for measuring these fluctuations in the time domain with a resolution of 120 ps is described. The results for several InGaAsP lasers show that intensity fluctuations in an injection laser are rather large, so that the probability of finding the output below 50 percent of the average power in a 120 ps time interval can be as high as 10^-5.