The influence of film crystallinity on the coupling efficiency of ZnO optical modulator waveguides
The influence of film crystallinity on the coupling efficiency of ZnO optical modulator waveguides
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DOI：
10.1088/0268-1242/10/11/015
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发表时间：
1995-11
影响因子：
1.9
通讯作者：
M. Koch;P. Timbrell;R. Lamb
中科院分区：
文献类型：
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作者：
M. Koch;P. Timbrell;R. Lamb
测量了溅射的c轴取向氧化锌（ZnO）薄膜在导波共振光调制器中的耦合效率。ZnO平面波导夹在SiO2/Si（100）衬底上的两个3 nm厚的铬层之间。这种新颖的设计有利于在棱镜耦合器设置中直接跨介电膜施加调制电压，从而避免跨二氧化硅（SiO2）光学隔离层的电压损耗。我们提出了四个不同制备的ZnO波导/调制器的比较，研究薄膜结晶度的耦合效率和电光参数的影响。ZnO波导的耦合效率被发现是依赖于膜的厚度和在膜的平面中测量的平均晶粒直径。当平均晶粒直径为26 nm时，对于低于300 nm的膜厚度可以实现高效率（0.76）。该值与均匀耦合器模型计算中预期的最大值（通常约为0.81）相当。
The coupling efficiencies of sputtered, c-axis-orientated zinc oxide (ZnO) films in guided wave resonance optical modulators have been measured. The ZnO planar waveguide is sandwiched between two 3 nm thick chromium layers on top of a SiO2/Si(100) substrate. This novel design facilitates application of a modulation voltage directly across the dielectric film in a prism coupler set-up and thus avoids voltage losses across the silicon dioxide (SiO2) optical isolation layer. We present a comparison of four differently prepared ZnO waveguides/modulators to investigate the influence of film crystallinity on the coupling efficiency and electro-optical parameters. The coupling efficiency of a ZnO waveguide is found to be dependent on both film thickness and average grain diameter measured in the plane of the film. A high efficiency (0.76) can be achieved for film thicknesses below 300 nm when the average grain diameter is 26 nm. This value is comparable to the maximum value of typically around 0.81 expected from model calculations for uniform couplers.