Improvement of slow light performance for vertical-cavity surface-emitting laser using coupled cavity structure

We propose a vertical cavity semiconductor emitting laser (VCSEL) using a coupled-cavity (CC) design to broaden the bandwidths of gain and delay spectra. The structure is formed by constructing a passive cavity coupled with the active cavity. By rendering the strength of the two resonant cavities, the increased gain bandwidth by 340% and the increased delay bandwidth by 800% are achieved as compared with the signal-cavity (SC) VCSEL. The wideband spectra present more square-like passband which is expected for slow light system. By using it, a 20 Gbit/s super Gaussian signal is delayed by about 13 ps with high quality.