Highly Sensitive Coupled Oscillator Based on an Exceptional Point of Degeneracy and Nonlinearity

We propose a scheme to obtain highly sensitive oscillators in coupled-resonator system with an exceptional point of degeneracy (EPD) and small instability. The oscillator the is realized by using two coupled resonators almost balanced small-signal gain loss, that saturates due nonlinear effects active component, resulting oscillation frequency very perturbation circuit. Two cases are investigated, parallel $LC$ loss either wirelessly mutual inductance or wired capacitor. This paper demonstrates theoretically experimentally conditions second-order EPD analyzes ultrasensitivity components' perturbation, including case asymmetric breaks $PT$ symmetry. discuss nonlinearity on performance how proposed improves sensing's sensitivity perturbations. In contrast previous methods, our degenerate can sense positive negative changes circuit component. may find applications various areas, such as ultrasensitive sensors, tunable oscillators, modulators.