Multi-energy nitrogen implantation into thermally grown SiO2 on silicon substrates has been performed and the optical wave-guiding properties of this structure has been studied. The implantation energy used was in Ie range of 40 KeV to 150 keV, and the doses used were typically 2×1016 to 2×10−2. The energies and doses were chosen to achieve relatively flat implanted nitrogen profiles. It is found that optical waveguides can be formed when the implanted nitrogen concentration is sufficiently high. Both prism-coupling technique and end-fire coupling technique were used to test the implanted waveguides fabricated. Many m-lines including dark modes were observed by the prism-coupling method. This structure is found to be very stable against thermal annealing and there is no significant change observed in the waveguiding properties even after annealing at 1000 °C for four hours. The waveguide loss was found to be typically 0.6 dB/cm before annealing and can be further reduced to about 0.3 dB/cm after annealing.