Planar and ridged waveguide preparation on erbium pre-implanted fused silica by multi-energy helium ion implantation and femtosecond laser ablation

Abstract

Ion implantation stands as a highly competitive technique for fabricating optical waveguide structures within photoelectric materials. In this work, both planar and ridge waveguides have been successfully realized on fused silica. The fabrication process begins with the implantation of erbium ions into fused silica, utilizing an energy of 400 keV and a fluence of 5×1015ions/cm2 to produce a fluorescence effect. Following this, helium ions are implanted at varying energies −450, 500, and 550 keV-with a consistent fluence of 3.2×1016ions/cm2 to create a planar waveguide structure. Subsequently, the ridge waveguide is meticulously prepared through the application of laser ablation, leveraging the pre-existing planar waveguide as a foundation. The guide mode of the planar waveguide is characterized at a wavelength of 632.8 nm using the prism coupling method. Additionally, the near-field light intensity distribution at the same wavelength is assessed via the end-face coupling technique and further analyzed using the finite-difference beam propagation method. To substantiate the practical utility of these waveguides, measurements of the propagation loss and fluorescence properties are conducted.