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US 6,636,669 B1Granted
Nanophotonic directional coupler device
AssigneeNorthwestern University
InventorsMee Koy Chin, Seng-Tiong Ho
Life of this patent
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Abstract
A nanophotonic directional coupler is disclosed for transferring light from one waveguide to a second waveguide. The directional coupler is formed within relatively small dimensional parameters and can be formed to accommodate light signals of both transverse electric (TE) and transverse magnetic (TM) polarizations.
Claims16
A directional coupler device for transferring light, said directional coupler device comprising:
- a first waveguide for propagating light therein, said first waveguide extending along a longitudinal axis and having an input port, an output port, and first and second portions defined therebetween;
- and,
- a second waveguide for propagating light therein, said second waveguide having an output port and first and second portions,
- wherein, said first portion of said first waveguide being spaced a first distance from said first portion of said second waveguide, said second portion of said first waveguide being spaced a second distance from said second portion of said second waveguide, said first distance being less than said second distance, wherein light propagating in said first waveguide from said input port towards said output port transfers from said first portion of said first waveguide to said first portion of said second waveguide and continues to propagate towards said output port of said second waveguide, and wherein said directional coupler device is formed with said first distance being determined as a function of a wavelength of the propagating light, and an index of refraction across said first distance and an index of refraction in at least the first waveguide to transfer light into the second waveguide with transverse electric polarization at substantially the same power factor as light with transverse magnetic polarization, regardless of the polarization characteristic of light propagating in the first waveguide, so that the light propagating in the second waveguide has the same polarization characteristic as light propagating through the first waveguide.
1 more element
A polarization independent directional coupler device for transferring light, said directional coupler device comprising:
- a first waveguide for propagating light therein, said first waveguide extending along a longitudinal axis and having an input port, an output port, and first and second portions defined therebetween;
- and,
- a second waveguide for propagating light therein, said second waveguide having an output port and first and second portions,
- wherein, said first portion of said first waveguide being spaced a first distance from said first portion of said second waveguide, said second portion of said first waveguide being spaced a second distance from said second portion of said second waveguide, said first distance being less than said second distance, wherein light propagating in said first waveguide from said input port towards said output port transfers from said first portion of said first waveguide to said first portion of said second waveguide and continues to propagate towards said output port of said second waveguide, and wherein said first distance is determined as a function of a wavelength of the propagating light, and an index of refraction across said first distance and an index of refraction in at least the first waveguide and is less than 0.5 μm.
1 more element
A polarization independent directional coupler device for transferring light, said directional coupler device comprising:
- a first waveguide for propagating light therein, said first waveguide extending along a longitudinal axis and having an input port, an output port, and first and second portions defined therebetween;
- and,
- a second waveguide for propagating light therein, said second waveguide having an output port and first and second portions,
- wherein, said first portion of said first waveguide being spaced a first distance from said first portion of said second waveguide determined as a function of a wavelength of the propagating light, and an index of refraction across said first distance and an index of refraction in at least the first waveguide, said second portion of said first waveguide being spaced a second distance from said second portion of said second waveguide, said first distance being less than said second distance, wherein light propagating in said first waveguide from said input port towards said output port transfers from said first portion of said first waveguide to said first portion of said second waveguide and continues to propagate towards said output port of said second waveguide, and wherein said first waveguide defines a width in said first portion, said width being greater than 0.25 μm and less than 0.35 μm.
1 more element
A polarization independent directional coupler device for transferring light, said directional coupler device comprising:
- a first waveguide for propagating light therein, said first waveguide extending along a longitudinal axis and having an input port, an output port, and first and second portions defined therebetween;
- and,
- a second waveguide for propagating light therein, said second waveguide having an output port and first and second portions,
- wherein said first portion of said first waveguide being spaced a first distance from said first portion of said second waveguide determined as a function of a wavelength of the propagating light, and an index of refraction across said first distance and an index of refraction in at least the first waveguide, said second portion of said first waveguide being spaced a second distance from said second portion of said second waveguide, said first distance being less than said second distance, wherein light propagating in said first waveguide from said input port towards said output port transfers from said first portion of said first waveguide to said first portion of said second waveguide and continues to propagate towards said output port of said second waveguide, and wherein said first portion of said first waveguide having a length of less than 50 μm.
1 more element
A polarization independent directional coupler device for transferring light, said directional coupler device comprising:
- a first waveguide for propagating light therein, said first waveguide extending along a longitudinal axis and having an input port, an output port, and first and second portions defined therebetween;
- and,
- a second waveguide for propagating light therein, said second waveguide having an output port and first and second portions,
- wherein, said first portion of said first waveguide being spaced a first distance from said first portion of said second waveguide determined as a function of a wavelength of the propagating light, and an index of refraction across said first distance and an index of refraction in at least the first waveguide, said second portion of said first waveguide being spaced a second distance from said second portion of said second waveguide, said first distance being less than said second distance, wherein light propagating in said first waveguide from said input port towards said output port transfers from said first portion of said first waveguide to said first portion of said second waveguide and continues to propagate towards said output port of said second waveguide, and wherein said first waveguide defines a width in said first portion, said width being greater than 0.35 μm.
1 more element
A polarization independent directional coupler device for transferring light, said directional coupler device comprising:
- a first waveguide for propagating light therein, said first waveguide extending along a longitudinal axis and having an input port, an output port, and first and second portions defined therebetween;
- and,
- a second waveguide for propagating light therein, said second waveguide having an output port and first and second portions,
- wherein said first portion of said first waveguide being spaced a first distance from said first portion of said second waveguide determined as a function of a wavelength of the propagating light, and an index of refraction across said first distance and an index of refraction in at least the first waveguide, said second portion of said first waveguide being spaced a second distance from said second portion of said second waveguide, said first distance being less than said second distance, wherein light propagating in said first waveguide from said input port towards said output port transfers from said first portion of said first waveguide to said first portion of said second waveguide and continues to propagate towards said output port of said second waveguide, and wherein said first waveguide defines a width in said first portion, said width being less than 0.25 μm.
1 more element
Dependencies are inferred from the claim text.