Weak-value amplification in fast and slow light in a ring resonator

We analyzed fast and slow light in a fiber-ring resonator in a framework of weak-value measurements, obtaining the explicit form of the interaction Hamiltonian. Here, we fully utilized the advantage of the fiber-ring resonator in experiments and directly observed the time delay of the circulating pulse inside the ring, as well as the delays of the total output pulses that traversed the system under different pre- and post-selection states. The mean arrival time of the total output pulse can be expressed as the delay time of the circulating pulse amplified by a factor that reflects the weak value, thus both fast and slow light in the fiber-ring resonator system are quantitatively described using the framework of weak-value amplification.