Choi Ju Won, Sohn Byoung-Uk, Chen George F R, Gao Hongwei, Mitchell William J, Ng Doris K T, Tan Dawn T H
Photonics Devices and System Group, Singapore University of Technology and Design, 8 Somapah Rd, Singapore, 487372, Singapore.
NanoFab Facility, Electrical and Computer Engineering Department, University of California Santa Barbara, Santa Barbara, CA, 93106, USA.
Nanophotonics. 2025 Apr 8;14(9):1333-1344. doi: 10.1515/nanoph-2024-0659. eCollection 2025 Apr.
Four-wave mixing is a widely used nonlinear process for wavelength conversion, parametric amplification and signal regeneration in various Kerr devices, which enables wavelength-tunability and lower-power operation in compact optical systems. Here, we demonstrate low-power continuous-wave four-wave mixing in an ultra-silicon-rich nitride topological waveguide leveraging the strong confinement of the Su-Schrieffer-Heeger topological structure and ultra-silicon-rich nitride platform's high Kerr nonlinearity and negligible nonlinear loss. We experimentally observe continuous-wave four-wave mixing at an ultra-low pump power of 510 µW, and wavelength tunability of 54 nm with on/off conversion efficiency of -57 dB at a pump power of 3 mW. We further investigate the efficiency of the four-wave mixing process when disorder is introduced into the Su-Schrieffer-Heeger waveguide array resulting in ±80 % randomness in the coupling coefficients. It is experimentally shown that similar conversion efficiencies are achieved in the presence and absence of disorder, indicating robustness against potential fabrication errors. We expect that this work can be applied to develop compact, tunable wavelength conversion systems operating at very low power levels which are robust against certain types of disorder.
四波混频是一种在各种克尔器件中广泛用于波长转换、参量放大和信号再生的非线性过程，它能在紧凑型光学系统中实现波长可调谐性和低功率运行。在此，我们利用Su-Schrieffer-Heeger拓扑结构的强限制以及富硅氮化物平台的高克尔非线性和可忽略不计的非线性损耗，在富硅氮化物拓扑波导中演示了低功率连续波四波混频。我们通过实验观察到在510 μW的超低泵浦功率下实现了连续波四波混频，在3 mW的泵浦功率下波长可调谐性为54 nm，开/关转换效率为 -57 dB。我们进一步研究了将无序引入Su-Schrieffer-Heeger波导阵列时四波混频过程的效率，这导致耦合系数出现±80%的随机性。实验表明，在有无无序的情况下都能实现相似的转换效率，这表明该过程对潜在的制造误差具有鲁棒性。我们期望这项工作可应用于开发紧凑、可调谐的波长转换系统，该系统能在非常低的功率水平下运行，并且对某些类型的无序具有鲁棒性。
