Synchronization and amplification enabled by diversity in nonlinear optical systems and the analogy with converse symmetry breaking for coupled oscillators

In this Research Letter it is shown how certain optical wave amplification phenomena, which do not obey standard phase-matching conditions and are generally classified as non-Hermitian phase matching or gain-through-loss(-filtering) processes, can be considered as particular cases of the more general phenomenon of converse symmetry breaking predicted and observed in various networks of coupled oscillators. It is shown that the abovementioned optical amplification processes are possible thanks to a phase-locking dynamics enabled by asymmetry or heterogeneity in the coupled-modes equations.