The past, present, and future of photonic integrated circuits in optical communications

Modern electronics began with the invention of the transistor and the discovery of minority carrier injection [1]. These advances have fundamentally improved and changed our modern world. Essential to this progress is the scalable nature of semiconductor technology and the invention of the integrated circuit (IC) [2, 3]. The IC has become ubiquitous and has had unparalleled impact on our modern world as a result of the ability of semiconductor and transistor technology to continually increase the functionality, performance, and reliability of solid-state circuits, while reducing their size, power, and costs. This scaling has been exponential, resulting in ICs today that contain over a billion transistors per chip with a cost per transistor of <;0.1 microcents. A key value of the IC is the ability to realize many of the aforementioned improvements by eliminating the need to discretely package and assemble individual devices or smaller circuits by providing the device and circuit connections via semiconductor batch and wafer scale processing.