Octave-spanning supercontinuum generation in a CMOS-compatible thin Si3N4 waveguide coated with highly nonlinear TeO2.

Supercontinuum generation (SCG) is an important nonlinear optical process enabling broadband light sources for many applications, for which silicon nitride (Si3N4) has emerged as a leading on-chip platform. To achieve suitable group velocity dispersion and high confinement for broadband SCG the Si3N4 waveguide layer used is typically thick (>∼700 nm), which can lead to high stress and cracks unless specialized processing steps are used. Here, we report on efficient octave-spanning SCG in a thinner moderate-confinement 400-nm Si3N4 platform using a highly nonlinear tellurium oxide (TeO2) coating. An octave supercontinuum spanning from 0.89 to 2.11 µm is achieved at a low peak power of 258 W using a 100-fs laser centered at 1565 nm. Our numerical simulations agree well with the experimental results giving a nonlinear parameter of 2.5 ± 0.5 W-1m-1, an increase by a factor of 2.5, when coating the Si3N4 waveguide with a TeO2 film. This work demonstrates highly efficient SCG via effective dispersion engineering and an enhanced nonlinearity in CMOS-compatible hybrid TeO2-Si3N4 waveguides and a promising route to monolithically integrated nonlinear, linear, and active functionalities on a single silicon photonic chip.

Thulium-doped tellurium oxide waveguide amplifier with 7.6 dB net gain on a silicon nitride chip: publisher's note.

This publisher's note contains corrections to Opt. Lett.44, 5788 (2019)OPLEDP0146-959210.1364/OL.44.005788.

Thulium-doped tellurium oxide waveguide amplifier with 7.6 dB net gain on a silicon nitride chip.

We report on thulium-doped waveguide amplifiers integrated on a low-loss silicon nitride platform. The amplifier structure consists of a thulium-doped tellurium oxide thin film coated on a silicon nitride strip waveguide on silicon. We determine a waveguide background loss of 0.7 dB/cm at 1479 nm based on the quality factor measured in microring resonators. Gain measurements were carried out in straight and 6.7-cm-long s-bend waveguides realized on a 2.2-cm-long chip. We measure internal net gain over the wavelength range 1860-2000 nm under 1620 nm pumping and up to 7.6 dB total gain at 1870 nm, corresponding to 1.1 dB/cm. These results are promising for the realization of highly compact thulium-doped amplifiers in the emerging 2 µm band for silicon-based photonic microsystems.