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Efficient photoinduced second-harmonic generation in silicon nitride photonics



Xiyuan Lu, Gregory Moille, Ashutosh Rao, Daron Westly, Kartik Srinivasan


Silicon photonics lacks a second-order nonlinear optical (chi(2)) response in general because the typical constituent materials are centro-symmetric and lack inversion symmetry, which prohibits chi(2) nonlinear processes such as second harmonic generation (SHG). Here, for the first time, we realize efficient SHG in an optical microresonator by combining a strong photo- induced effective chi(2) nonlinearity and resonant enhancement via perfect-phase matching. We show a record-high conversion efficiency of (2,500 +/- 100) %/W, which is 2 to 4 orders of magnitude larger than previous works. In particular, our devices realize mW-level SHG output powers with > 20 % power conversion efficiency. This demonstration is a major breakthrough in realizing efficient chi(2) processes in silicon photonics, and paves the way for integrated self-referencing of Kerr frequency combs for compact optical frequency synthesis and optical clock technologies.
Nature Photonics


Lu, X. , Moille, G. , Rao, A. , Westly, D. and Srinivasan, K. (2020), Efficient photoinduced second-harmonic generation in silicon nitride photonics, Nature Photonics, [online],, (Accessed February 29, 2024)
Created November 2, 2020, Updated October 12, 2021