Bounds on higher-order Lorentz-violating photon sector coefficients from an asymmetric optical ring resonator experiment

•Data collected from orientation-modulated optical ring resonator frequency comparison.•Bounded higher-order parity-odd nonbirefringent Lorentz-violating coefficients.•First bounds placed on two linear combinations of d=8d=8 parity-odd coefficients.

Optical resonators provide a powerful tool for testing aspects of Lorentz invariance. Here, we present a reanalysis of an experiment where a path asymmetry was created in an optical ring resonator by introducing a dielectric prism in one arm. The frequency difference of the two fundamental counter-propagating modes was then recorded as the apparatus was orientation-modulated in the laboratory. By assuming that the minimal Standard-Model Extension coefficients vanish we are able to place bounds on higher-order parity-odd Lorentz-violating coefficients of the Standard-Model Extension. The results presented in this work set the first constraints on two previously unbounded linear combinations of d=8d=8 parity-odd nonbirefringent nondispersive coefficients of the photon sector.