Yuan Liang, Shi Jianhong, Chen Xianfeng
Department of Physics, The State Key Laboratory on Fiber Optic Local Area Communication Networks and Advanced Optical Communication Systems, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.
Appl Opt. 2011 Dec 1;50(34):6352-7. doi: 10.1364/AO.50.006352.
We theoretically investigate an all-optical isolator under arbitrary linearly polarized fundamental wave (FW) input in an optical superlattice (OSL). The scheme is based on simultaneously phase matching the first-order Type I (oo-e) quasi-phase-matching (QPM) second-harmonic generation (SHG) process and higher-order Type 0 (ee-e) QPM SHG process in an OSL with a defect inserted in an asymmetrical position. Simulation results show that the contrast ratio of the all-optical isolator can maintain close to 1 under arbitrary linearly polarized FW. Thus, an all-optical isolator based on an OSL that is not sensitive to the direction of linear polarization can be realized. We also show that, with the defect in a strong asymmetry position, the length of the defect can be designed flexibly to maintain a high contrast ratio. Additionally, if the length of the OSL is longer, the nonreciprocal response can be realized for low optical intensities.
我们从理论上研究了光学超晶格（OSL）中在任意线性偏振基波（FW）输入下的全光隔离器。该方案基于在具有不对称位置插入缺陷的OSL中，同时使一阶I型（oo - e）准相位匹配（QPM）二次谐波产生（SHG）过程和高阶0型（ee - e）QPM SHG过程相位匹配。模拟结果表明，在任意线性偏振FW下，全光隔离器的对比度可保持接近1。因此，可以实现基于对线性偏振方向不敏感的OSL的全光隔离器。我们还表明，当缺陷处于强不对称位置时，可以灵活设计缺陷长度以保持高对比度。此外，如果OSL的长度更长，则对于低光强度可以实现非互易响应。
