Professor Blumenthal's group releases latest integrated sub-hertz linewidth laser findings

"Sub-hertz fundamental linewidth photonic integrated Brillouin laser"
_{Sarat Gundavarapu, Grant M. Brodnik, Matthew Puckett, Taran Huffman, Debapam Bose, Ryan Behunin, Jianfeng Wu, Tiequn Qiu, Cátia Pinho, Nitesh Chauhan, Jim Nohava, Peter T. Rakich, Karl D. Nelson, Mary Salit & Daniel J. Blumenthal}

^{Nature Photonics volume 13, pages 60–67 (2019)}

Photonic integrated sub-hertz linewidth lasers will enable systems-on-chip solutions for a wide range of high-end and commercial applications, including coherent communications, next-generation data centre networks, atomic and quantum sensing, and atomic clocks. Translating the performance of these spectrally pure lasers to wafer-scale integrated devices will bring lower cost, size, weight and power along with increased environmental robustness to applications that, today, are relegated to the laboratory scale. In addition, an integration platform that supports operation across the visible to infrared (~405 to 2,350 nm) will provide a versatile spectrally pure optical source solution.

Abstract: Spectrally pure lasers, the heart of precision high-end scientific and commercial applications, are poised to make the leap from the laboratory to integrated circuits. Translating this performance to integrated photonics will dramatically reduce cost and footprint for applications such as ultrahigh capacity fibre and data centre networks, atomic clocks and sensing. Despite the numerous applications, integrated lasers currently suffer from large linewidth. Brillouin lasers, with their unique properties, offer an intriguing solution, yet bringing their performance to integrated platforms has remained elusive. Here, we demonstrate a sub-hertz (~0.7 Hz) fundamental linewidth Brillouin laser in an integrated Si3N4 waveguide platform that translates advantages of non-integrated designs to the chip scale. This silicon-foundry-compatible design supports low loss from 405 to 2,350 nm and can be integrated with other components. Single- and multiple-frequency output operation provides a versatile low phase-noise solution. We highlight this by demonstrating an optical gyroscope and a low-phase-noise photonic oscillator.

Read the full publication here.

Read the UCSB Current's detailed coverage of the group's discovery here.