Paper Title
A REVIEW ON KERR OPTICAL FREQUENCY COMBS

Abstract
Abstract - Optical frequency combs are structures consisting of numerous spectral lines or comb teeth, each one being equidistant from its neighbor. Its contribution in precision spectroscopy was awarded one half of the Nobel prize in physics in 2005. Since then, optical frequency combs have piqued the interest of researchers, leading to increased research and focus on the subject. They find their use in a wide array of fields such as metrology, photonics, optical communication etc. Mode locked lasers have been the conventional and most commonly used technique in producing a frequency comb. However, due to a recent growing interest in frequency combs and their potential applications, a new class of combs based on the use of nonlinear effects have been discovered. They operate on the principle of parametric frequency conversion inside special optical cavities termed microresonators, which supporthigh Qvalues and low mode-volumes, allowing for thegeneration of frequency combs through parametric frequency conversion via four-wave mixing. This class of combs are known as Kerr frequency combs, as they rely on the Kerr nonlinearity for their conception. In this paper, we review and discuss the relevant physics behind these Kerr combs. We take a look at the Ikeda map, which describes the evolution of the intracavity field. The Lugiato-Lefever equation, another formalization of the field, is which is a simpler description for the field evolution is covered, providing a temporal model of comb generation. We provide a review of how the technology of frequency combs has progressed approximately over the last two decades, from when it was conceived, and the theory behind its working along with its applications and future scope in different branches of science. Keywords - Kerr Frequency Combs; Microresonators; Four-Wave Mixing; Lugiato-Lefever Equation.