Editorial

Abstract

We are pleased to serve as the Guest Editors of this Special Issue on the topic of Optical Frequency Combs, published by the IEEE Photonics Technology Letters (PTL) journal. The science and technology of optical frequency combs (OFCs) have developed dramatically in the last few decades, and frequency combs have evolved to become a key enabling tool for a myriad of pertinent applications, from ultrahigh-precision metrology and spectroscopy to novel, exciting uses in high-speed telecommunications, advanced microwave signal generation and processing, astronomy observations, and even for quantum information processing and computing. The field of OFCs continues attracting a great deal of attention and keeps progressing in several important directions. OFC technologies based upon mode-locked lasers are very mature, so current research is mainly directed towards implementations in integrated formats, such as frequency combs generated in micro-resonator devices, or in alternative designs with enhanced capabilities, such as platforms based upon electro-optic modulation or frequency-shifted laser cavities. Intensive research is being also conducted toward the utilization of OFCs across the above-mentioned practical application areas and others.