Optical attenuation filter
AssigneeOptical Coating Laboratory, Inc.
InventorsRalf H. Erz, Scott McEldowney, Lauren R. Wendt
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Abstract
This invention relates to attenuation filters having absorbing thin film layers, which comprises gray metals or metal compounds. The attenuation filters offer significant advantages when used in optical communication systems wherein they are subjected to a relatively high flux of incident light. It was surprisingly discovered that particular thin film materials provide significant protection to the attenuating thin films layer thereby improving the temporal stability and power handling capacity over prior art devices.
Claims21
An optical attenuation filter comprising:
- a. a substrate having a first surface and a second surface,
- b. an attenuating layer deposited on at least a portion of the first surface of said substrate,
- c. a buffer layer having a refractive index less than about 1.65 in optical communication with said attenuating layer,
- d. one or more additional layers in optical communication with said buffer layer, said one or more additional layers comprising a first layer having a refractive index greater than about 1.65 deposited onto said buffer layer
- whereby said buffer layer and said one or more additional coating layers comprise an antireflective coating for said attenuating layer to provide a low reflectivity wavelength band.
The optical attenuation filter of claim 1
- wherein the variation of transmission is less than about 0.5% over the low reflectivity wavelength band from 1525 to 1630 nm.
An optical attenuation device comprising:
- a. an optical signal input port,
- b. an optical signal output port,
- c. An optical attenuation filter disposed between said input port and said output port, for intercepting an optical beam carrying one or more optical signal channels, said attenuation filter comprising,
- i. a substrate having a first and second surface;
- ii. an attenuating layer deposited on a least a portion of the first surface of said substrate;
- iii. a buffer layer having a refractive index less than about 1.65 in optical communication with said attenuating layer;
- iv. one or more additional layers in optical communication with said buffer layer, said one or more additional layers comprising a first layer having a refractive index greater than about 1.65 deposited onto said buffer layer;
- d. a translating stage supporting said optical attenuation filter wherein said translating stage is adapted for selective translation of said optical attenuation filter in a direction substantially parallel to the surface of said substrate.
An optical attenuation filter comprising:
- a. a substrate having a first surface and a second surface,
- b. an attenuating layer deposited on at least a portion of the first surface of said substrate,
- c. a buffer layer having a refractive index less than about 1.65 in optical communication with said attenuating layer,
- d. one or more additional layers in optical communication with said buffer layer, said one or more additional layers comprising a first layer having a refractive index greater than about 1.65 deposited onto said buffer layer,
- wherein said buffer layer comprises a material selected from the group consisting of silicon monoxide, silicon dioxide, SiOx (wherein x is less than 2), aluminum oxide and mixtures thereof,
- whereby said buffer layer and said one or more additional coating layers comprise an antireflective coating for said attenuating layer and provide a wavelength band of substantially uniform transmission.
Dependencies are inferred from the claim text.