Methods to Obtain High-Contrast-Ratio Twisted Nematic Liquid Crystal Device at Wavelength of 1.55 μm

摘要

A very high contrast ratio 90° twisted nematic (TN) liquid crystal device at a wavelength of 1.55 μm is a very useful optical component in fiber optical interconnections, but it is not easy to obtain. In this paper the reasons for some difficulties in achieving a high contrast ratio are explained and a practical way to fabricate a high contrast ratio TN cell is provided. Using this method we fabricated many TN cells at a wavelength of 1.55 μm and achieved a contrast ratio higher than 40 dB.