On-chip non-Hermitian optical parametric amplifiers with a large bandwidth
On-chip non-Hermitian optical parametric amplifiers with a large bandwidth
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DOI：
10.1364/josab.426956
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发表时间：
2021-07
影响因子：
1.9
通讯作者：
Asif Ahmed;Xiang Meng;Q. Zhong;R. El-Ganainy;R. Osgood;J. Dadap
中科院分区：
文献类型：
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作者：
Asif Ahmed;Xiang Meng;Q. Zhong;R. El-Ganainy;R. Osgood;J. Dadap
最近，我们的团队引入了基于非厄米相位匹配的光学参量放大的概念，其中引入损耗可以在这个非线性光学过程中产生增益。以前使用二阶非线性光学耦合模理论的模拟结果已经证明了该技术作为一种替代严格的相位匹配条件的潜力，而这种条件在半导体平台中通常是难以实现的。在这里，我们通过考虑硅纳米线中的参数放大来加强这一概念用于三阶非线性的情况，并通过使用真实的材料和几何参数来使用严格的有限差分时域分析来说明这些器件的可行性。特别地，我们证明了通过系统地控制四波混频过程中的闲置损耗，我们可以实现从泵浦到信号分量的有效单向能量转换，即使在违反典型的相位匹配条件的情况下也是如此。重要的是，我们的模拟表明，在几百纳米(∼600 nm)的大带宽上，对于几毫米的波导长度，可以获得9db的∼信号增益。这一带宽比传统的基于硅光子学的四波混频过程所能实现的带宽大近两个数量级。
Recently, our groups have introduced the notion of optical parametric amplification based on non-Hermitian phase matching wherein the incorporation of loss can lead to gain in this nonlinear optical process. Previous simulation results using second-order nonlinear optical coupled-mode theory have demonstrated the potential of this technique as an alternative to the stringent phase-matching condition, which is often difficult to achieve in semiconductor platforms. Here we fortify this notion for the case of third-order nonlinearity by considering parametric amplification in silicon nanowires and illustrate the feasibility of these devices by employing rigorous finite-difference time-domain analysis using realistic materials and geometric parameters. Particularly, we demonstrate that by systematic control of the optical loss of the idler in a four-wave mixing process, we can achieve efficient unidirectional energy conversion from the pump to the signal component even when the typical phase-matching condition is violated. Importantly, our simulations show that a signal gain of ∼9dB for a waveguide length of a few millimeters is possible over a large bandwidth of several hundreds of nanometers (∼600nm). This bandwidth is nearly 2 orders of magnitude larger than what can be achieved in the conventional silicon-photonics-based four-wave mixing process.