Nabil Ghada, Ho Wing Fat, Chan Hau Ping
Electronic Engineering Department, City University of Hong Kong, Kowloon Tong, Hong Kong, China.
Appl Opt. 2013 Aug 1;52(22):E15-21. doi: 10.1364/AO.52.000E15.
We applied polymer dispersed liquid crystal (PDLC) as the cladding material in a polymer-based variable optical attenuator. Three polymer inverted channel waveguides were fabricated, two with PDLC upper cladding (aligned PDLC and nonaligned PDLC) and one with aligned liquid crystal upper cladding. Upon operation, the waveguides with aligned upper claddings show relatively lower threshold and cutoff voltages compared to those with nonaligned PDLC cladding. But the waveguide with nonaligned PDLC upper cladding shows lower polarization dependence and a higher attenuation range of 39 and 41.37 dB for TM and TE modes, respectively, over a tuning field strength of 0.9 V/μm.
我们将聚合物分散液晶（PDLC）用作基于聚合物的可变光衰减器中的包层材料。制作了三条聚合物倒置通道波导，其中两条带有PDLC上包层（取向PDLC和非取向PDLC），一条带有取向液晶上包层。在工作时，与非取向PDLC包层的波导相比，带有取向包层的波导显示出相对较低的阈值电压和截止电压。但是，带有非取向PDLC上包层的波导显示出较低的偏振依赖性，并且在0.9 V/μm的调谐场强下，TM模式和TE模式的衰减范围分别高达39 dB和41.37 dB。
