Patent ID: 7817703

Claim:
A Vertical-Cavity Surface-Emitting Laser (VCSEL) comprising: a substrate; a first semiconductor multilayer film reflective mirror of a first conductivity type, formed on the substrate and having a first impurity concentration; an active region, formed on the first semiconductor multilayer film reflective mirror; a second semiconductor multilayer film reflective mirror of a second conductivity type, formed on and in proximity to the active region and having a second impurity concentration; a third semiconductor multilayer film reflective mirror of the second conductivity type, formed on the second semiconductor multilayer film reflective mirror and having a third impurity concentration; and a fourth semiconductor multilayer film reflective mirror of the second conductivity type, formed on the third semiconductor multilayer film reflective mirror and having a fourth impurity concentration, the first, second, third and fourth semiconductor multilayer film reflective mirrors comprising a pair of a low-Al semiconductor layer having a relatively low Al-composition and a high-Al semiconductor layer having a relatively high Al-composition, the Al-composition of the low-Al semiconductor layer in the second semiconductor multilayer film reflective mirror being higher than the Al-composition of the low-Al semiconductor layer in the fourth semiconductor multilayer film reflective mirror, and the second impurity concentration being lower than the fourth impurity concentration, the third impurity concentration being higher than the second impurity concentration and the third impurity concentration being higher than the fourth impurity concentration.