Resonantly enhanced nonreciprocal silicon Brillouin amplifier

Nils T. Otterstrom, Eric A. Kittlaus, Shai Gertler, Ryan O. Behunin, Anthony L. Lentine, Peter T. Rakich

Research output: Contribution to journalArticlepeer-review

43 Scopus citations


The ability to amplify light within silicon waveguides is central to the development of high-performance silicon photonic device technologies. To this end, the large optical nonlinearities made possible through stimulated Brillouin scattering offer a promising avenue for power-efficient all-silicon amplifiers, with recent demonstrations producing several dB of net amplification. However, scaling the degree of amplification to technologically compelling levels (>10 dB), necessary for everything from filtering to small signal detection, remains an important goal. Here, we significantly enhance the Brillouin amplification process by harnessing an intermodal Brillouin interaction within a multi-spatial-mode silicon racetrack resonator. Using this approach, we demonstrate more than 20 dB of net Brillouin amplification in silicon, advancing state-of-the-art performance in silicon waveguides by a factor of 30. This level of amplification is achieved with modest (∼15 mW) continuous-wave pump powers and produces low out-of-band noise. Moreover, we show that this same system behaves as a unidirectional amplifier, providing more than 28 dB of optical nonreciprocity without insertion loss in an all-silicon platform. Building on these results, this device concept opens the door to new types of all-silicon injection-locked Brillouin lasers, high-performance photonic filters, and waveguide-compatible distributed optomechanical phenomena.

Original languageEnglish (US)
Pages (from-to)1117-1123
Number of pages7
Issue number9
StatePublished - 2019

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics


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