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Six‐wave mixing induced by free‐carrier plasma in silicon nanowire waveguides
Author(s) -
Zhou Heng,
Liao Mingle,
Huang ShuWei,
Zhou Linjie,
Qiu Kun,
Wong Chee Wei
Publication year - 2016
Publication title -
laser and photonics reviews
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.778
H-Index - 116
eISSN - 1863-8899
pISSN - 1863-8880
DOI - 10.1002/lpor.201600124
Subject(s) - four wave mixing , mixing (physics) , mesoscopic physics , silicon , nanowire , kerr effect , sideband , optics , dispersion (optics) , materials science , nonlinear optics , free carrier , optoelectronics , free carrier absorption , physics , nonlinear system , laser , condensed matter physics , quantum mechanics , microwave
Abstract Nonlinear wave mixing in mesoscopic silicon structures is a fundamental nonlinear process with broad impact and applications. Silicon nanowire waveguides, in particular, have large third‐order Kerr nonlinearity, enabling salient and abundant four‐wave‐mixing dynamics and functionalities. Besides the Kerr effect, in silicon waveguides two‐photon absorption generates high free‐carrier densities, with corresponding fifth‐order nonlinearity in the forms of free‐carrier dispersion and free‐carrier absorption. However, whether these fifth‐order free‐carrier nonlinear effects can lead to six‐wave‐mixing dynamics still remains an open question until now. Here we report the demonstration of free‐carrier‐induced six‐wave mixing in silicon nanowires. Unique features, including inverse detuning dependence of six‐wave‐mixing efficiency and its higher sensitivity to pump power, are originally observed and verified by analytical prediction and numerical modeling. Additionally, asymmetric sideband generation is observed for different laser detunings, resulting from the phase‐sensitive interactions between free‐carrier six‐wave‐mixing and Kerr four‐wave‐mixing dynamics. These discoveries provide a new path for nonlinear multi‐wave interactions in nanoscale platforms.