Abstract
Photonic switching increases the speed and efficiency of light in fiber-optic tele-communications and computing applications. Light can transmit multiple non-interfering data signals on different wavelengths over a larger distance at higher speed, while copper wires have a limited bandwidth. With copper-based communications, electromagnetic interference (EMI) can interrupt data transmission, and the integrated circuits cannot send and receive enough data to take advantage of their increasing processing power. Optical integrated circuits using significantly less space allow for a much robust data transmission. Furthermore, fiber optics are immune to EMI allowing for transmission over larger distance and fewer repeater amplifiers. A new class of miniaturized optical components fabricated on substrates of silicon or electro-optic material, including photodetectors, lasers, light modulators, waveguides, and optical filters for use as multiplexers and demultiplexers in wavelength division multiplexing, encode data on different wavelengths of light, and then transmit and decode it. The article has discussed the fundamentals to the state-of-the-art advances in photonic switching and communications, elucidating on all essential components in switching and communications, such as photoconduction; photodetection; lasers; charge-coupled imagers; electro-optic, quantum well and acousto-optic modulation and devices, and radio-frequency photonic links.