WHITE LIGHT-EMITTING DIODES (LEDs) are considered the "green"
alternative to conventional lighting methods. After all, they
offer lower power consumption, lower voltage, longer lifetime,
smaller size, and cooler operation than other lighting options.
LEDs also can be used as a wireless communications transmitter.
This capability stems from the fast response time and modulation
of visible light for wireless communications. An optical
wireless communications system that uses white LEDs for indoor
wireless networks was recently investigated by Yonsei
University's (Seoul, Korea) Yong-Hwan Son, Sung-Chan An, Hyun-
Seung Kim, Yong-Yuk Won, and Sang-Kook Han. The researchers
faced a challenge in that the visible-light-communication (VLC)
link had to be efficiently connected to the existing optical
access network. Their solution was to use a VLC link based on an
optical access network that relied on both LED and an electro-
absorption transceiver (EAT). The EAT, in turn, is based on an
electro-absorption modulator. Whe