Tunable optical filters with liquid crystal resonators
OwnerAaron J. Zilkie, Atul Pradhaninventors
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Abstract
A voltage-tuned optical filter that is low cost and simple to fabricate uses cascaded etalon modules, each module comprising a liquid crystal etalon, such as a Fabry-Perot etalon, having a relatively small Free Spectral Range (FSR). At least two of the modules are provided with a voltage control to enable Vernier tuning control. For a given overall scan, the voltage-tuned optical filter may operate with reduced voltage ranges for each liquid crystal etalon.
Claims20
A method for tuning an optical filter having at least two voltage controlled Fabry-Perot liquid crystal etalon modules N1 and N2, wherein the overall filter has a required total free spectral range (FSR) of X, and module N1 has an FSR of X1 which is in the range 0.008X to 0.5X, and module N2 has an FSR of X2 that is less than X1 and in the range 0.008X to 0.5X, the method comprising:
- simultaneously changing the voltage of the N1 and N2 modules over a range of V1 to V2.
An optical filter, having a required total free-spectral range (FSR) of X, comprising:
- a liquid crystal Fabry-Perot etalon module N1, the module N1 having a Free Spectral Range (FSR) of X1, which is in the range 0.008X to 0.5X;
- an N1 voltage control for controlling the voltage of the module N1;
- a liquid crystal Fabry-Perot etalon module N2 spaced from and optically aligned with the module N1, the module N2 having a FSR of X2 that is less than X1 and in the range 0.008X to 0.5X;
- and
- an N2 voltage control for controlling the voltage of the module N2.
An optical filter having a plurality of liquid crystal etalon modules connected in a cascaded manner, wherein a Free Spectral Range (FSR) of the optical filter is X and the FSR of each of the etalon modules is equal to or less than 0.5*X.
Dependencies are inferred from the claim text.