Low-frequency noise characteristics of Pb-salt semiconductor lasers

The low-frequency noise characteristics of several stripe-geometry Pb-salt semiconductor diode lasers were investigated in the 4-11-microm spectral region. Excess noise is observed to vary as the ratio of I/I(t), where I is the injection current and I(t) is the threshold value at which lasing action begins. The magnitude of the diode laser excess noise has been measured to be 24 dB above shot noise at threshold.