Ultralow 0.034 dB/m loss wafer-scale integrated photonics realizing 720 million Q and 380 μW threshold Brillouin lasing

• Published in: Optics letters Vol. 47; no. 7; p. 1855
• Main Authors: Liu, Kaikai, Jin, Naijun, Cheng, Haotian, Chauhan, Nitesh, Puckett, Matthew W, Nelson, Karl D, Behunin, Ryan O, Rakich, Peter T, Blumenthal, Daniel J
• Format: Journal Article
• Language: English
• Published: United States 01.04.2022
• ISSN: 1539-4794
• DOI: 10.1364/OL.454392

We demonstrate 0.034 dB/m loss waveguides in a 200-mm wafer-scale, silicon nitride (Si N ) CMOS-foundry-compatible integration platform. We fabricate resonators that measure up to a 720 million intrinsic Q resonator at 1615 nm wavelength with a 258 kHz intrinsic linewidth. This resonator is used to realize a Brillouin laser with an energy-efficient 380 µW threshold power. The performance is achieved by reducing scattering losses through a combination of single-mode TM waveguide design and an etched blanket-layer low-pressure chemical vapor deposition (LPCVD) 80 nm Si N waveguide core combined with thermal oxide lower and tetraethoxysilane plasma-enhanced chemical vapor deposition (TEOS-PECVD) upper oxide cladding. This level of performance will enable photon preservation and energy-efficient generation of the spectrally pure light needed for photonic integration of a wide range of future precision scientific applications, including quantum, precision metrology, and optical atomic clocks.