Comparison of the instantaneous and averaged emission spectra of an injection laser operating under spiking conditions

A comparison was made of the multimode emission spectra of an injection laser obtained by averaging over a time interval not exceeding 10^–10 sec ("instantaneous" spectrum) and over an interval equal to 10⁵ pumping pulses ("averaged" spectrum). In the presence of strong spiking, the instantaneous spectra of single spikes differed considerably from the averaged spectrum and consisted of random selections of modes from the set observed in the averaged spectrum. A random distribution of photons over the oscillation modes at the beginning of a spike was assumed to determine the instantaneous spectrum. The spikes disappeared under single-mode emission conditions.