| Several novel modulation concepts are developed for a composite-resonator vertical-cavity laser (CRVCL) with the objective to extend laser bandwidth beyond that of a conventional vertical-cavity surface-emitting laser (VCSEL), and several new device applications for optical communication and signal processing are also discovered. For each modulation concept the modulation characteristics of the CRVCL are studied with rate-equation analysis. The rate-equation theory shows not only that the CRCVL can engineer and/or optimize the modulation response, but also that it has an inherent advantage in achieving higher modulation bandwidth than a conventional VCSEL. In order to facilitate high speed modulation experiments, a new device structure for the CRVCL is designed and fabricated. Specifically, a ground-signal-signal-ground coplanar contact is incorporated into the CRVCL structure. The experimental results of CRVCL modulation using different modulation concepts are presented, and their correlation with the rate-equation theory is also discussed. The CRVCL exhibits unique modulation characteristics that cannot be achieved by a conventional VCSEL. Finally, with unique modulation characteristics, the CRVCL enables several new device applications for optical communication and signal processing, including multilevel amplitude modulation, signal pre-emphasis, microwave signal mixing, and synchronous electrical and optical signaling. |
