US Patent 7801192 Monitoring method and VCSEL array with monitoring function

VCSEL array with a structure in which vertical cavity surface emitting devices are arranged on a substrate. The VCSEL array includes first and second optical devices. The second optical device receives light that is directed parallel to the substrate and emitted from the first optical device and converts the light into an electric signal when a voltage applied to the second optical device is switched to a reverse bias. The second optical device emits light that is directed parallel to the substrate when a voltage applied to the second optical device is switched to a forward bias.