  Chirality refers to the property that an object and its mirror image cannot
overlap each other by spatial rotation and translation, and can be found in
various research fields. We here propose chiral chaos and construct a chiral
chaotic device via coupled whispering gallery mode resonators, where routes to
chaos exhibit pronounced chirality for two opposite pumping directions. The
mechanism responsible for this phenomenon is that time-reversal symmetry of the
traveling-wave light fields is broken by the Rayleigh scatterers inserted in
resonators. Combining with the Lyapunov exponents, we propose metrics to
measure the symmetry and chirality between different chaotic dynamics. We find
that such a chiral chaotic device can be applied to achieve sensing with high
sensitivity, wide detectable range, and strong robustness to the phase and
orientation randomness of weak signals. Our work presents a promising candidate
for on-chip sensing and may have applications in quantum networks and chaotic
communications.
