Vacuum-ultraviolet laser direct writing of buried waveguides in fused silica bulk glass.

摘要

This thesis presents the internal processing of fused silica to shape 3-D photonic structures by 157 nm F₂ laser. A large 0.4 numerical aperture Schwarzschilds lens in the novel optical processing system was used to tightly focus the F₂ beam a few hundreds micrometer below the surface of fused silica and induce buried refractive index changes without damage to the glass surface. The processing windows for writing optical waveguides and directional couplers are presented. The optical properties of the waveguides including beam profiles, scattering loss, coupling efficiency and birefringence are discussed in detail.; To the author's knowledge, the 3-D buried waveguides represent the first such a demonstration for nanosecond-duration ultraviolet laser sources. This makes an important extension to long pulse lasers since such buried structures have only been formed by ultrafast lasers to date. The results point to new manufacturing processes for the F₂ laser for fabrication of photonic components.