Multiple thin film absorption of reflected substrate modes in waveguide system
AssigneeThe United States of America as represented by the Secretary of the Navy
InventorsArnold H. Singer, Ronald T. Holm
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Abstract
Reduction of light reflections in substrate modes. The use of absorbing multilayer thin-film light interference coatings on the backside of a LiNbO.sub.3 substrate provides an optical system which substantially reduces reflected substrate modes in integrated optical spectrum analyzers at around 8300 A wavelength, or at other selected wavelengths, over a broad range of incident angles by selection of individual film thickness and optical constants.
Claims21
An optical waveguide system with reduced substrate reflections comprising:
- a substrate;
- a thin-film optical waveguide on the frontside of the substrate for carrying light therethrough;
- and
- an absorbing antireflective multilayer coating on the backside of the substrate;
- whereby light of substantially a single wavelength having leaked into the substrate and incident to the backside of the substrate over a broad range of angles is substantially absorbed by the antireflecting coating with minimal reflection.
An optical waveguide system with reduced substrate reflections comprising:
- a substrate;
- a thin-film optical waveguide on the frontside of the substrate for carrying light therethrough;
- and
- an absorbing antireflective coating on the backside of the substrate comprising:
- a first layer of transparent material;
- a second layer of material being moderately lossy;
- and
- a third layer of material being highly lossy;
- whereby light of substantially a single wavelength having leaked into the substrate and incident to the backside thereof over a broad range of angles is substantially absorbed with minimal reflection.
Dependencies are inferred from the claim text.