Analogue modulation performance of 20 GHz vertical cavity surface emitting lasers for radio over fiber applications

Abstract

The analog modulation performance in terms of linearity and modulation of IEEE 802.11g signals with carrier frequencies of up to 20GHz is reported. An oxide aperture Vertical Cavity Surface Emitting Laser (VCSEL) with a low current density and 20GHz 3dB bandwidth is shown to operate at 70°C with an SFDR better than 80dB/Hz ⅔ upto 20GHz. This is only a slight reduction in performance over the behavior at 20°C. A novel integrated Electro-Optically Modulated (EOM) VCSEL is shown to offer a bandwidth of 18GHz with better performance in-terms of SFDR. However it currently suffers greater temperature dependence and lower optical output power.