Abstract

Recently quadratic dispersive optical resonators have been considered as new sources for frequency comb generation [1-3]. In contrast to Kerr combs, quadratic ones may operate with decreased pump power and can achieve spectral regions non accessible before. These combs in the frequency spectrum correspond to different type of dissipative structures circulating inside the cavity. Therefore the understanding of the dynamics of such structures is of crucial importance. In particular here we focus on the study of localized structures (LSs) since they correspond to broadband, coherent temporal pulses with a fixed repetition rate, which are one of the most important waveforms for frequency comb generation. To do so we consider a dispersive cavity with a quadratic medium phase matched for degenerate optical parametric oscillations (OPOs), and driven by an electric field at frequency 2ω₀ in a doubly resonant configuration. This type of cavities can be described by a mean-field model for the slowly varying envelopes A, and B, of the electric field centered at frequencies ω₀ and 2ω₀, respectively [4]. These equations are formally equivalent to those describing diffracting cavities [5], although in this case a large walk-off d, related with the difference of group velocities between the fields A and B, is present.

© 2019 IEEE