Abstract
We present a method for modification of silicon nitride (Si(3)N(4)) waveguide resonators using femtosecond laser annealing. The quality (Q) factor of the waveguide resonators can be improved by approximately 1.3 times after annealing. Notably, waveguides that originally had a high Q value maintained their quality after the annealing process. However, those with a lower initial Q value experienced a noticeable improvement post-annealing. To characterize the annealing effect, the surface morphologies of Si(3)N(4) films, both pre- and post-annealing, were analyzed using atomic force microscopy. The findings suggest a potential enhancement in surface refinement. Furthermore, Raman spectroscopy confirmed that the Si(3)N(4) film's composition remains largely consistent with its original state within the annealing power range of 0.6-1.6 W. This research underscores the potential of femtosecond laser annealing as an efficient, cost-effective, and localized technique for fabricating low-loss integrated photonics.