Ultrahigh-Q photonic crystal nanocavities and their applications

Light is fast and thus can carry large amounts of data in a very short time, which makes photonic technology a promising communication tool. In fact, photonic technologies, such as optical ber, that support a high transmittance speed1 are becoming more important in our lives. However, these technologies have had limited practical applications in data transmission, and signal processing has yet to nd a commercial use. Although all-optical signal processing has been widely studied for several decades,2 it has been difcult to employ in practical systems, often because the required operating energy was too large.3,4 This is due to the fundamental nature of light. In other words, light is fast but difcult to store or conne in a small space. This makes photonic approaches difcult to handle. In contrast, there is a growing demand for a practical all-optical signal processor because today the network system bandwidth is often limited by the speed of the electronics used at network nodes.