Add-drop device for a wavelength division multiple, fiber optic transmission system
AssigneeRutgers University
InventorElias Snitzer
Life of this patent
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Abstract
Device for use in adding or dropping light signals at predetermined center wavelengths to or from a wavelength division multiplex, fiber optic transmission system. The device includes an evanescent wave coupler having a coupling region formed from two single mode waveguides, the coupling region being formed so that there is substantially complete evanescent field coupling of light from one waveguide to the other in a predetermined wavelength band. Further, the device has a Bragg grating disposed in the coupling region in each of the waveguides.
Claims18
A device for use in coupling light signals having wavelengths in a region at a predetermined wavelength out of or into a transmission system which carries light signals, the device comprising:
- an evanescent wave coupler having a coupling region formed from two single mode waveguides, wherein size and spacing of the waveguides in the coupling region are fabricated having dimensions determined by a condition that the coupling region is sufficiently long for complete evanescent field coupling of light from one waveguide to the other in a predetermined wavelength band, the coupling region has a length which is equal to a distance which provides complete evanescent field coupling of light in the band from one waveguide to the other, which length is referred to as a half-beat-length, said waveguides having a core therein;
- and
- a Bragg grating disposed in said core at the center of the coupling region in each of the waveguides, said center of said Bragg grating occurring at a distance equal to one quarter beat length from an end of the coupling region.
A device for use in coupling light signals having wavelengths in a region at a predetermined wavelength out of or into a transmission system which carries light signals, the device comprising:
- an evanescent wave coupler having a coupling region formed from two single mode waveguides, wherein size and spacing of the waveguides in the coupling region are fabricated having dimensions determined by a condition that the coupling region is sufficiently long for complete evanescent field coupling of light from one waveguide to the other in a predetermined wavelength band, a Bragg grating disposed in said core of the coupling region in each of the waveguides, wherein the coupling region has a length which is equal to even multiples of a distance for complete evanescent field coupling of light from one waveguide to the other in the predetermined wavelength band to occur, which length is referred to as a half-beat-length.
A device for use in coupling light signals having wavelengths in a region at a predetermined wavelength out of or into a transmission system which carries light signals, the device comprising:
- an evanescent wave coupler having a coupling region formed from two single mode waveguides, wherein size and spacing of the waveguides in the coupling region are fabricated having dimensions determined by a condition that the coupling region is sufficiently long for complete evanescent field coupling of light from one waveguide to the other in a predetermined wavelength band, a Bragg grating disposed in said core of the coupling region in each of the waveguides, wherein the coupling region has a length which is equal to odd multiples of a distance for complete evanescent field coupling of light from one waveguide to the other in the predetermined wavelength band to occur, which length is referred to as a half-beat-length.
A device for use in coupling light signals having wavelengths in one or more regions at a predetermined wavelength out of or into a transmission system which carries light signals, the device comprising:
- a first device comprised of a first evanescent wave coupler having a first coupling region formed from two single mode waveguides, wherein the size and spacing of the waveguides in the first coupling region are fabricated having dimensions determined by a condition that the coupling region is sufficiently long for complete evanescent field coupling of light from one waveguide to the other in a first predetermined wavelength band;
- a Bragg grating disposed in the first coupling region in each of the waveguides;
- a second device comprised of a second evanescent wave coupler having a second coupling region formed from two single mode waveguides, wherein the size and spacing of the waveguides in the second coupling region are fabricated having dimensions determined by a condition that the coupling region is sufficiently long for complete evanescent field coupling of light from one waveguide to the other in the first predetermined wavelength band;
- and
- a Bragg grating disposed in the second coupling region in each of the waveguides;
- wherein one of the waveguides from the first device is coupled to one of the waveguides from the second device.
Dependencies are inferred from the claim text.