Patent ID: 6094246
Filing Date: 2000-07-25
Classification: G02F

Abstract:
A twisted nematic liquid crystal electro-optic modulator for use in an infrared optical communications system comprising:first and second spaced apart cell walls;a liquid crystal material positioned between said first and second spaced apart cell walls;electrodes positioned to impose an electric potential across said liquid crystal material;entrance and exit polarizers respectively receiving and exiting infrared light within a wavelength range of about 1480 nm to about 1630 nm, said entrance and exit polarizers respectively defining entrance and exit polarization directions;wherein said first and second cell walls are configured to respectively define first and second liquid crystal director directions, said first and second directions being angularly offset by an amount defining a twist angle, wherein said twist angle is greater than 0 degrees and less than 90 degrees; andwherein said polarization direction of said entrance polarizer and said first liquid crystal director direction is angularly offset by an amount defining a beta angle, wherein said beta angle is between about 8 degrees and about 17 degrees to provide an extinction ratio, within a wavelength range of about 1480 nm to about 1630 nm, of at least about -25 dB.