Higher-order exceptional points in an optical fiber using stimulated Brillouin scattering

We induce a third-order exceptional point (EP3) in an optical fiber using stimulated Brillouin scattering. The versatility of the approach allows to scan the parameter space and plot all three eigenvalue sheets, revealing cubic root dispersion and symmetry-induced structures such as lines of exceptional points of second order. Our work provides a new platform for studying exceptional points, with implications for enhanced sensors and optical nonlinearity for neuromorphic photonic systems. This fabrication-free approach paves the way for further research into non-Hermitian systems.