LOW-FREQUENCY INTENSITY NOISE IN SEMICONDUCTOR-LASERS

The low-frequency intensity noise at 25 MHz of a Fabry-Perot semicondu ctor laser is measured as a function of injection current. All the mea surements are taken at room temperature and the laser is operated with a commercial current source (the conditions under which laser diodes are often used). At the highest injection current of twice threshold, the intensity noise is 5.5 dB above the shot-noise limit. When the lon gitudinal side mode suppression of the laser is 20 dB or larger, the i ntensity noise is modeled adequately by an expression derived from the single-mode, small-signal, linearized, semiclassical rate equations. All the parameters used in the theory are derived or referenced. (C) 1 996 Optical Society of America