Transverse Inscription of Silicon Waveguides by Picosecond Laser Pulses

Abstract

In this work, picosecond laser inscription of segmented waveguides in crystalline silicon based on a deterministic single‐pulse modification process is demonstrated. Pulses of 43 ps duration at 1.55 wavelength are used to transversely inscribe periodic structures with a pulse‐to‐pulse pitch of ≈2 . Infrared shadowgraphy images and Raman spectroscopy measurements indicate that the modifications exhibit a spherical shape. Characterization of waveguide performance at 1.55 for various pulse energies and periods is carried out. Direct comparison with numerical simulations confirms the presence of graded index waveguides, encompassing a micrometer core size and a maximum refractive index change of . This short‐pulse inscription approach can pave the way for 3D integrated photonic devices in the bulk of silicon.