Experimental observations of breathing Kerr temporal cavity solitons at large detunings

Abstract

It was recently predicted that, due to stimulated Raman scattering, temporal Kerr cavity solitons may exhibit oscillatory instabilities at large cavity detunings [Phys. Rev. Lett.120, 053902 (2018)PRLTAO0031-900710.1103/PhysRevLett.120.053902]. Here, we report experimental observations of this behavior. To access the appropriate oscillatory regime, we construct a macroscopic fiber ring resonator with a high finesse of F≈240. By synchronously driving the resonator with flat-top nanosecond pulses, we can reach very large intracavity power levels, where Raman-induced soliton oscillations can be observed. We also surprisingly find that, in the limit of large cavity driving strengths, new soliton instability regimes that are not accounted for in the known bifurcation structure of driven Kerr resonators can emerge even in the absence of Raman effects. Our experimental results are in good agreement with numerical simulations.

Stability analysis of numerically exact time-periodic breathers in the Lugiato-Lefever equation: Discrete vs continuum

“…IV D illustrates the continuation of strongly discrete oscillating cavity solitons into continuum LLE breathers; and Sec. IV E confirms and explains the existence of stable LLE breathers in a regime of large detuning, which was recently observed experimentally [11]. Finally, some concluding remarks are presented in Sec.…”

“…Our last example considers a regime of large detuning and driving where, somewhat unexpectedly, stable breathers were found recently, experimentally as well as in direct numerical simulations for the continuous LLE [11]. With our notation, the regime studied in [11] corresponds to E 0 = 20 √ 5 ≈ 45 and −90 −80. However, as can be inferred, e.g., from Fig.…”

“…Thus, for E 0 = 45, stable stationary solitons exist for −2500 −54 and so there is a regime of coexistence between the stable stationary soliton and stable breather, the origin of which was unclear in Ref. [11].…”

“…Attempting to reproduce the breather from [11] within the framework of the discrete model (2), we first note that very large values of C are needed in this regime to get close to a continuumlike breather, due to its large amplitude. Specifically, with = −85 we could obtain a breather for C = 500, but suffering from discreteness-induced period-doubling instabilities analogous to those discussed in Secs.…”

“…Adding driving and damping terms to the NLS equation yields the Lugiato-Lefever equation (LLE) [6], which has become the paradigmatic equation for studying various nonlinear phenomena in optical cavities with dissipation [7][8][9]. In contrast to the conservative KM breathers, the nonzero background of the LLE breathers may be stabilized by dissipation, and there have been several experimental works in recent years confirming their existence as attractors for suitable parameter values and initial conditions, for macroscopic fiber cavities [10,11], and for optical microresonators [12][13][14][15][16][17][18].…”