Spectral signatures of exceptional points and bifurcations in the fundamental active photonic dimer

The fundamental active photonic dimer consisting of two coupled quantum well lasers is investigated in the context of the rate-equation model. Spectral transition properties and exceptional points are shown to occur under general conditions, not restricted by parity-time symmetry as in coupled-mode models, suggesting a paradigm shift in the field of non-Hermitian photonics. The optical spectral signatures of system bifurcations and exceptional points are manifested in terms of self-termination effects and observable drastic variations of the spectral line shape that can be controlled in terms of optical frequency detuning and inhomogeneous pumping.