A Normal form for Frequency Combs and Localized States in Time-Delayed Kerr-Gires-Tournois Interferometers

Recently, an alternative method for the generation of phase-locked optical frequency combs (OFCs) with tunable repetition rate that maintain the high optical power levels characteristic of VECSELs was proposed using a first principle model relying on delay algebraic equations (DAEs) [1], [2]. A schematic setup of the system is presented in Fig. 1(a). It is composed of a disk-shaped monomode micro-cavity similar to a VCSEL structure but that contains a nonlinear Kerr medium. The micro-cavity is closed by two distributed Bragg mirrors with reflectivities
$r_{1,2}$
, whereas the long external cavity with round-trip time
$\tau\gg\tau_{c}$
is closed by a feedback mirror with reflectivity
$\eta$
and the feedback phase
$\phi$
.