Linear optical switching in a FLC/waveguide composite device

Integrated optic devices using liquid crystals: design and fabrication issues

“…The latter can be derived from the director orientation, which minimizes the free-energy of the LC 43 . The following values for the elastic constants and the other relevant parameters were considered: 11 =6.4 pN, 22 =4 pN, 33 =10 pN, dielectric anisotropy =11.8, and pretilt angle of 2°. The operation point results from a small variation of the applied voltage, typically some 10 mV from the bias at about 3 V. …”

“…The main advantage in using polymeric waveguides consists of depositing a polymeric buffer layer between indium tin oxide (ITO) layer used for the electrodes and the optical waveguide in order to reduce losses due to ITO absorption especially at wavelengths of C-band of interest for optical communications 20 . Modulation of light amplitude was also demonstrated by employing an active FLC cladding overlaying an optical waveguide 21,22 . An integrated optical switch was demonstrated in which a light beam in a polymer waveguide can be switched towards either of two distinct output ports by means of total internal reflection by changing refractive index of NLC used as overlayer 23 .…”