A hybrid group IV ridge waveguide platform is demonstrated, with potential application across the optical spectrum from ultraviolet to the far infrared wavelengths. The waveguides are fabricated by partial etching of sub-micron ridges in a nanocrystalline diamond thin film grown on top of a silicon wafer. To create vertical confinement, the diamond film is locally undercut by exposing the chip to an isotropic fluorine plasma etch via etch holes surrounding the waveguides, resulting in a mechanically stable suspended air-clad waveguide platform. Optical characterization of the waveguides at 1550 nm yields an average optical loss of 4.67 ± 0.47 dB/mm. Further improvement to the fabrication process is expected to significantly reduce this waveguide loss.

Publisher's PDF, also known as Version of record Cyswllt i'r cyhoeddiad / Link to publication Dyfyniad o'r fersiwn a gyhoeddwyd / Citation for published version (APA):

A hybrid diamond/silicon air-clad ridge waveguide platform is demonstrated. The air-clad structure coupled with the wide transmission window of diamond can allow for the use of this architecture over a large wavelength range, especially for the longer infrared wavelengths. In order to provide vertical confinement, the silicon substrate was isotropically etched using SF 6 plasma to create undercut diamond films. An in-depth analysis of the etch characteristics of this process was performed to highlight its potential to replace wet isotropic etching or XeF 2 isotropic vapour phase etching techniques. The performance of the waveguide at 1550 nm was measured, and yielded an average loss of 4.67 +/-0.47 dB/mm. Index Terms-diamond integrated photonics, infrared waveguides, isotropic etching, plasma etching, sulfur hexafluoride