Sputtered silica waveguides with an embedded three-dimensional structure

Single-mode sputtered silica waveguides (SS guides) are fabricated by filling channels of 8-μm width in a silica substrate with core silica material and embedding with a cladding layer. Silica deposition process is carried out by bias sputtering. The measured waveguide loss was 1.2 dB/cm. The change of cross-sectional profile in the sputtering process on the channel is analyzed with the result in good agreement with experiments. The optimum sputtering condition for filling the channel is elucidated. The method is applied to embedding gratings fabricated on the silica substrate.