Optical coupler for measuring wavelength
AssigneeHoneywell International Inc.
InventorsBogdan Szafraniec, Charles Lange
Life of this patent
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Abstract
An optical coupler for measuring mean wavelength of a broadband optical source is described. Sensitivity of the optical coupler to variations of refractive index and coupler length is minimized. The sensitivity to the variations of the refractive index is minimized by making a difference between the group refractive indices of the symmetric and asymmetric propagation modes approximately constant and independent of the refractive index. The sensitivity to the variations of the coupler length is minimized by selecting the coupler length that makes output powers from two waveguides to the first order insensitive to its length. This selection is possible for broadband optical sources.
Claims15
An optical coupler, comprising in combination:
- a first waveguide;
- and
- a second waveguide in close proximity to the first waveguide forming a coupling region, wherein dimensions of the first and second waveguides are selected to minimize variations of a difference in group delay indices of a symmetric propagation mode and an asymmetric propagation mode in response to changes of refractive index.
2-3. (canceled)
An optical coupler, comprising in combination:
- a first waveguide;
- and
- a second waveguide in close proximity to the first waveguide forming a coupling region, wherein a gap is located between the first and second waveguides in the coupling region, wherein dimensions of the first and second waveguides and a width of the gap are selected to minimize sensitivity to the changes of the refractive index, and wherein a length of the coupling region is selected based on a spectral shape of the broadband optical source.
A method for forming an optical coupler that is sensitive to a mean optical wavelength of a broadband optical source and substantially insensitive to changes of refractive index and coupler length, comprising in combination:
- selecting dimensions of a first waveguide and a second waveguide, wherein selecting the dimensions of the first and second waveguides includes selecting the dimensions to minimize variations of a difference in group delay indices of a symmetric propagation mode and an asymmetric propagation mode in response to the changes of the refractive index;
- positioning the first waveguide to be in a close proximity to the second waveguide to form a coupling region, wherein the positioning includes:
- selecting a width of a gap between the first and second waveguides, and
- selecting a length of the coupling region.
12-13. (canceled)
Dependencies are inferred from the claim text.