Photonic integrated circuits (PICs) integrate optical and electronic components onto a single chip using materials like lithium niobate, gallium arsenide, and indium phosphide. PICs can be classified as either hybrid or monolithic. They aim to bring fiber optic networks directly to subscribers by enabling high data transmission rates over long distances with minimal loss, noise, voltage, and power requirements. Key components in PICs include lasers, photodetectors, waveguides, power splitters, and optical amplifiers.