Digital glass forming of photonics

Abstract

.We investigate the digital glass forming process for depositing commercial SMF-28 single-mode optical fiber for photonic purposes. The process utilizes a CO2 laser to locally heat the feedstock to fuse it onto a fused quartz substrate. We focus on how altering the deposition parameters, including the laser power, feed rate, and path plan, affects the deposited fiber morphology and how this affects the optical transmission. At high powers, the fiber bonds strongly to the substrate, resulting in significant changes in fiber morphology and core shape. With a gradient transition between the feedstock geometry and the deposition geometry, high optical transmission for straight line depositions can be achieved. Additional work was performed examining the optical losses when the fiber is deposited around a constant radius curve for different fiber morphologies, with higher losses recorded for higher power samples. Comparing the doping profile of these samples indicates that the gradient of Ge decreases at higher laser power, suggesting the losses are caused by diffusion of the fiber core. This work shows that for high input powers, the optical losses around curves are increased, leading to a tradeoff between the bonding strength and optical transmission for these geometries.