Fourier Domain Mode Locking: Method and Apparatus for the Generation of Fast Frequency Swept Waveforms and Chirped Pulses by Resonant Frequency Tuning

A system for reducing a repetition time of a frequency swept waveform, the system comprising: a laser, comprising a gain medium disposed within an optical cavity; a modulation means configured to modulate a gain medium of the laser, the laser and the gain medium configured to generate a unidirectional frequency sweep waveform having a repetition time; a separating optical element configured to separate the unidirectional frequency sweep waveform into at least two portions; a delay optical element configured to introduce a time delay between the at least two portions; a recombination optical element configured to recombine the at least two portions upon introduction of the time delay, and at least one polarization controller to control the polarization of at least one of the two portions of the frequency sweep waveform; wherein the time delay introduced by the optical delay element is selected so that the recombination optical element recombines the at least two portions of the unidirectional frequency sweep waveform substantially without an overlap, and further wherein the separating optical element, the delay optical element and the recombination optical element are disposed outside of the optical cavity. H:\mka\Interwoven\NRPortbl\DCC\MKA\7512099_1.docx - 27/2/15 WO 2010/047936 PCT/US20091'059324 I' CD (WThlD "I cc)~ JEUBLISJOIJI0 0.) 0 = ;eub3~s 10)JU03 to .aq qun a4 C)0