Sputtered Aluminum Nitride Waveguides for the Telecommunication Spectrum with less than 0.16 dB/cm Loss

TL;DR

This paper demonstrates sputtered aluminum nitride waveguides with record low propagation losses suitable for telecommunication wavelengths, highlighting their potential for integrated photonics.

Contribution

It reports the fabrication of sputtered AlN waveguides with the lowest losses in the C-band and first in the O-band, comparable to epitaxially grown counterparts.

Findings

Propagation loss of 0.137 dB/cm at 1310 nm

Propagation loss of 0.154 dB/cm at 1550 nm

First report of sputtered AlN waveguides in the O-band

Abstract

We report the fabrication and characterization of photonic waveguides from sputtered aluminum nitride (AlN). The AlN films were deposited on 6" silicon substrates with a 3 $\mu$m buried silicon oxide layer using reactive DC magnetron sputtering at a temperature of 700{\deg}C. The resulting uncladded polycrystalline waveguides exhibit propagation losses of 0.137 $\pm$ 0.005 dB/cm at wavelengths of 1310 nm and 0.154 $\pm$ 0.008 dB/cm at a wavelength of 1550 nm in the TE polarization. These results are the best reported for sputtered AlN waveguides in the C-band and the first report in the O-band. These performances are comparable to those of the best-reported AlN waveguides, which are epitaxially grown by metal-organic chemical vapor deposition (MOCVD) on sapphire substrates. Our findings highlight the potential of sputtered AlN for photonic platforms working in the telecom spectrum.