A design of reflection‐type polarization control device using ferroelectric liquid crystals

Abstract

AbstractFor a planar polarization control optical switch proposed by the authors for optical communication networks, a reflection‐type liquid crystal polarization control device (PCD) that can emit the incident wave in the same direction as the incident after totally reflected on the back side and can accurately switch the polarization direction of the optical wave by 90° in response to an applied voltage is needed. The authors have previously derived and reported a design theory for accurate switching of the polarization direction for an obliquely incident ferroelectric liquid crystal polarization control device (FLC‐PCD) in which the light wave is obliquely incident upon the device surface at an arbitrary angle and transmits to the back side. In the present paper, based on this theory, the polarization control characteristics are theoretically analyzed by means of the Jones matrix with respect to the reflection‐type FLC‐PCD, in which the incident wave is totally reflected at the back side of the device and is returned to the incident side. The condition for accurate switching of the polarization direction of the output wave by 90° is derived. Based on this condition, a method for derivation of the optimum design values of the liquid crystal layer thickness and liquid crystal optical axis angle is presented. The polarization control characteristics of the device fabricated for trial are measured, demonstrating the validity of the present design method. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 87(1): 43–53, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10038