  Lithium niobate(LN) microresonator is a key component in photonic integrated
circuits. An intriguing phenomenon was observed that the quality factor for
specific modes of the resonator can be further improved by femtosecond laser
irradiation. The high repetition laser pulses scatters into the cavity by
forming a defect on the surface and is confined in the edge. A localized
coupled laser refining process will then repair the lattice disorders and tiny
burrs on the periphery. The intrinsic quality factor of a measured mode can be
promoted from 2.17$\times$10$^5$ to 1.84$\times$10$^6$ indicating one order of
magnitude improvement. This highly controllable method has its own unique
advantages in improving the quality of an integrated resonator which opens new
prospects for single component engineering of LN photonic integrated circuits.
