Abstract

The discovery of passive mode-locking via saturable absorbers [1] has led to optical femto-second pulses with applications ranging from eye-surgery to the analysis of chemical reactions on ultra-short timescales. In the frequency domain a train of such optical pulses corresponds to a frequency comb (equidistant optical laser lines spaced by the pulse repetition rate) [2], which finds use in precision spectroscopy and optical frequency metrology [3]. Not relying on mode-locking, frequency combs can also be generated in continuously driven, high-quality-factor Kerr-nonlinear optical microresonators (cf. Fig. 1a) via cascaded four-wave mixing [4].

© 2013 IEEE