De Lucia F, Keefer D W, Corbari C, Sazio P J A
Opt Lett. 2017 Jan 1;42(1):69-72. doi: 10.1364/OL.42.000069.
Thermal poling is a well-known technique for inducing second-order nonlinearities in centrosymmetric silica optical fibers. However, some 25 years since its discovery, there still remain a number of issues that prevent the realization of very long length, highly efficient all-fiber nonlinear device applications that include frequency conversion or sources of polarization-entangled photon pairs. In this Letter, we report a thermal poling method that utilizes a novel range of liquid metal and aqueous electrodes embedded into the optical fibers. We demonstrate that it is possible to pole samples that are potentially meters in length, characterized by very low losses for efficient second-harmonic generation processes. The maximum estimated effective value of χ (0.12 pm/V) obtained using mercury electrodes is the highest reported in periodically poled silica fibers.
热极化是一种在中心对称石英光纤中诱导二阶非线性的知名技术。然而，自其发现约25年来，仍存在一些问题阻碍了实现包括频率转换或偏振纠缠光子对源在内的非常长长度、高效全光纤非线性器件应用。在本信函中，我们报告了一种热极化方法，该方法利用了嵌入光纤中的一系列新型液态金属和水性电极。我们证明，有可能对长度可能达数米的样品进行极化，其特点是在高效二次谐波产生过程中损耗极低。使用汞电极获得的χ的最大估计有效值（0.12皮米/伏）是周期性极化石英光纤中报道的最高值。
