Fabrication of buried channel waveguides in fused silica by focused MeV ion-beam irradiation

摘要

Abstract: Single mode buried optical waveguides have been fabricated in fused silica by irradiation with a focussed beam of MeV hydrogen ions (protons). The technique has the potential to direct write waveguide devices and produce multi-layered structures, without the need for intermediate steps such as mask fabrication or the subsequent deposition of layers of material. Two different `near-field' optical techniques have been used to measure the near-field mode- field pattern produced by these waveguides at 670 nm and 633 nm. Methods are described for determining the refractive index distribution within single mode buried waveguides from their output intensity distributions via an inversion of the scalar wave equation. In addition, confocal Raman spectrometry has been used to map out the damage profile within the waveguiding region. Propagation losses of approximately 3 dB.cm$+$MIN@1$/ have been measured in unannealed samples, which decrease to less than 0.5 dB/cm$+$MIN@1$/ after thermal annealing at 500$DGR@C for sixty minutes.!12