Self-Consistent Approach for Calculation of VCSEL Spectra Under Deep Microwave Current Modulation

We develop a self-consistent approach to calculate the spectra of the vertical-cavity surface-emitting lasers under a deep microwave modulation of the injection current. The treatment consists of solving a coupled system of equations for the concentration of electrons in the active medium and those for the amplitudes of spectral components derived from Maxwell’s equations. Their numerical solution demonstrates the specific asymmetry of experimental laser spectra under microwave modulation of the injection current. The presented method also accounts for the simultaneous modulation at multiple frequencies. We demonstrate that the laser spectrum can be controlled to some extent, namely, its carrier can be suppressed and the ratio of the first sidebands powers can be simultaneously changed by additional modulation of the injection current at doubled frequency. In addition, we show that the phase difference of these components is stable under variations of modulation parameters in a relatively wide range.