Kim Sangsik, Qi Minghao
Opt Express. 2015 Apr 20;23(8):9968-78. doi: 10.1364/OE.23.009968.
We present a polarization rotation and coupling scheme that rotates a TE(0) mode in a silicon waveguide and simultaneously couples the rotated mode to a hybrid plasmonic (HP(0)) waveguide mode. Such a polarization rotation can be realized with a partially etched asymmetric hybrid plasmonic waveguide consisting of a silicon strip waveguide, a thin oxide spacer, and a metal cap made from copper, gold, silver or aluminum. Two implementations, one with and one without the tapering of the metal cap are presented, and different taper shapes (linear and exponential) are also analyzed. The devices have large 3 dB conversion bandwidths (over 200 nm at near infrared) and short length (< 5 μm), and achieve a maximum coupling factor of ∼ 78% with a linearly tapered silver metal cap.
我们提出了一种偏振旋转和耦合方案，该方案可在硅波导中旋转TE(0)模式，并同时将旋转后的模式耦合到混合等离子体（HP(0)）波导模式。这种偏振旋转可以通过由硅条形波导、薄氧化物间隔层和由铜、金、银或铝制成的金属帽组成的部分蚀刻非对称混合等离子体波导来实现。本文给出了两种实现方式，一种是金属帽有锥度的，一种是没有锥度的，并且还分析了不同的锥度形状（线性和指数型）。这些器件具有较大的3 dB转换带宽（近红外时超过200 nm）和较短的长度（<5μm），并且使用线性锥形银金属帽时可实现高达约78%的最大耦合系数。
