We investigate niobium oxide (NbO) as an alternative waveguide material for applications in the visible spectral range. NbO has a refractive index ranging between 2.3 and 2.35, which is about 25% higher than SiN, the most widely used material for waveguides in the visible spectral range. This increased index contrast between NbO and the cladding material allows to fabricate optical components with much smaller footprint, and consequently to increase the density of photonic integrated circuits substantially. We benchmark this waveguide platform to imec’s CMOS compatible PECVD SiN platform and observe fairly similar loss numbers for both materials.
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