244nm Direct UV Written Gratings in SiNx layers

Silicon nitride (SiN
x
) is a versatile photonic integrated circuit (PIC) platform due to its large transparency window, low nonlinear loss, high refractive index contrast, and the ability to vary optical properties through different deposition techniques [1]–[3]. Recent studies have demonstrated the ability to change the refractive index of SiNx layers through exposure to 244nm radiation from an argon-ion laser [3], [4]. In this work, we utilize this phenomenon to laser-inscribe gratings in layers of various compositions of SiN
x
.