Modulation characteristics of a laser-diode hybrid-integrated into a ceramic multilayer module for radio-over-fiber applications

In the context of the augmented demand for high capacity and uninterrupted communication links, radio-over-fiber technology provides advantage in terms of reduced power dissipation and broad operational frequency bandwidth. In such a link, a vertical-cavity surface-emitting laser plays an important role as an optical source, due to its real-time RF modulation capability, and consequently, the understanding of its characteristics in the microwave frequency range is of utmost importance. Therefore, in this paper the input impedance characteristics have been studied with the aid of an equivalent circuit. The similarity between the measured and simulated return loss reveals the accuracy of the equivalent circuit. The dynamic characteristics such as the relaxation resonance frequency and the damping factor at different bias currents have been extracted from the modulation response, and the bandwidth limitation due to damping has been studied.