Patent ID: 7196744

Claim:
An optical attenuator, comprising: a variable liquid crystal rotator comprising: an at least semi-transparent liquid crystal device; and a plurality of electrodes configured to conduct electricity to the at least semi-transparent liquid crystal device such that the polarization axis of a light signal transmitted through the liquid crystal device will be varied by an amount proportional to the magnitude of the electricity applied to the plurality of electrodes; a first polarizing element having an optical polarization axis, wherein the first polarizing element receives the light signal from the variable liquid crystal rotator and transmits a portion of the light signal proportional to the angular difference between the optical polarization axis of the light signal and that of the first polarizing element; a faraday rotator configured to receive the portion of the light signal from the first polarizing element and rotate the optical polarization axis of the portion of the light signal; a second polarizing element having an optical polarization axis, wherein the second polarizing element receives the portion of the light signal and transmits a second portion of the light signal proportional to the angular difference between the optical polarization axis of the portion of the light signal and that of the second polarizing element.