Optical clustering for unsupervised learning using coupled microring resonators

Learning in biological systems is thought to depend on the phenomena of clustering. For example, new experiences are most easily remembered by attaching them to a category of related prior knowledge, that is, by clustering. Clustering in the brain is thought by some to involve coupling of oscillator neurons. Therefore, we investigate clustering in frequency with an all-optical system. The system consists of a set of coupled microring lasers whose natural frequencies are set to the values to be clustered. We assume that closer values represent more similar information and that the values set the microring natural frequencies. A microring resonant frequency in such a system is influenced away from its natural frequency by interactions with its neighbors. As a result, the frequencies of the microrings will adjust themselves into a few groups or clusters. Equations are developed for a pair of microring resonators to show that the microring resonators will interact to perform clustering.