Frequency modulation of GaAlAs injection lasers at microwave frequency rates

Frequency modulation of GaAlAs double heterostructure injection lasers at microwave frequencies is reported for the first time. The lasers are operating at a 0.85 μm wavelength and have been modulated at frequencies up to 2.25 GHz with a modulation index of 2.4. The laser FM modulation is displayed by a high resolution spectral measuring setup comprising a monochromator and a Fabry-Perot interferometer. A simple laser model is presented which allows the static frequency shift of the laser resonance frequency to be calculated as a function of the bias current change. The results are compared with measured data.