Electrochemical driven self-holding optical actuator: from materials to device concepts

在本提案的框架内，我们将开发一种新型的自持式电化学驱动光学执行器。我们的主要目标是评估用于执行器的有前途的材料，并表明我们的方法与硅光子学兼容。执行器的目的是控制光子芯片上的光传输。驱动原理是基于覆盖硅波导选定区域的混合离子-电子导体（MIEC）材料。通过波导传播的光波受到与MIEC材料近场耦合的影响。我们采用了电致变色材料V2O5和WO3作为光调制器的基材。锂和氢都将作为MIEC材料插层的移动离子。电化学反应可以改变MIEC材料的离子含量。随着化学计量学的变化，光学性质，即折射率和消光系数，以及在底层波导中传播的光波的强度和相位也将被改变。为了证明使用MIEC材料作为光学致动器的概念，将采用溅射沉积方法制备固态多层系统。多层堆叠的电化学性能能够通过施加的电压/电流调节MIEC材料的离子含量，从而调节其光学性能。通过在硅光子电路上集成致动器系统，研究其光调制能力。为此，多层堆叠将沉积在各种硅波导结构的明确区域，这些结构以前是通过电子束光刻结合反应离子蚀刻制造的。将实验得到的硅波导致动器系统的光学性能与仿真进行比较，通过多次迭代的实验与仿真对比，得到设计和性能都优化的致动器材料系统。

In the framework of this proposal we will develop a novel self-holding electrochemically driven optical actuator. Our key goal is to evaluate promising materials used for the actuator and to show that our approach is compatible with silicon photonics. The purpose of the actuator is the control of light transmission on photonic chips. The actuation principle is based on mixed ionic-electronic conductor (MIEC) materials that cover selected areas of silicon waveguides. Light waves propagating through the wave guide are affected by near-field coupling to the MIEC material. As base material for the optical modulator we use the electrochromic materials V2O5 and WO3. Both lithium and hydrogen will be used as mobile ions for the intercalation of the MIEC material. The ion content of the MIEC material can be changed by electrochemical reactions. With this change in stoichiometry also the optical properties, i.e., the refractive index and the extinction coefficient and thus the intensity and phase of light waves propagating in the underlying waveguide will be modified. In order to prove the concept of using MIEC materials as optical actuators, solid-state multilayer systems will be fabricated by sputter deposition. The electrochemical performance of the multilayer stack enables to adjust the ion content of the MIEC material and thus its optical properties by the voltage/current applied. The optical modulation capability will be studied by integrating the actuator system on silicon photonic circuits. For this purpose, the multilayer stack will be deposited in well-defined areas of various silicon waveguide structures that were fabricated before by means of electron beam lithography in combination with reactive ion etching. The optical properties of the silicon waveguide-actuator system derived from our experiments are compared with simulations in order to obtain an actuator material system with optimized properties in terms of design and performance from the comparison between experiment and simulation after several iterations.