VERTICAL-CAVITY SURFACE-EMITTING LASER, MODULE, OPTICAL TRANSMISSION DEVICE, OPTICAL TRANSMISSION SYSTEM, FREE SPACE OPTICAL COMMUNICATION DEVICE, AND FREE SPACE OPTICAL COMMUNICATION SYSTEM

摘要

Provided is a VCSEL that includes a first semiconductor multilayer film reflective mirror of a first conductivity type formed on a substrate and having a first impurity concentration; an active region formed thereon; a second semiconductor multilayer film reflective mirror of a second conductivity type formed on and close to the active region and having a second impurity concentration; a third semiconductor multilayer film reflective mirror of the second conductivity type formed thereon and having a third impurity concentration being higher than the second impurity concentration; and a fourth semiconductor multilayer film reflective mirror of the second conductivity type formed thereon and having a fourth impurity concentration being higher than the second impurity concentration. The reflective mirrors include a pair of a low-Al semiconductor layer and a high-Al semiconductor layer. The Al-composition of the low-Al semiconductor layer in the second reflective mirror is higher than that of the fourth mirror.