Modulation response of multiple transverse modes in vertical-cavity surface-emitting lasers

The small-signal modulation response of multiple transverse modes in a vertical-cavity surface-emitting laser was studied numerically. The overlap between the modal distribution of the field and the carrier distribution in the active region is fundamental to determining the modulation response, According to the injection current level, the modulation response curve in several configurations and parameters used can display peaks and notches that may impair the frequency response of the device. These features reflect the competition of carrier by the operating modes in a way that can be described as interference. Therefore, the total modulation response curve cannot be evaluated from the modulation response of the individual modes.