Distributed reflector in a microring resonator
View Patent ↗A component having a microring resonator and grating, coupled to a waveguide is described. By selection of the grating period, and other parameters such as the grating-waveguide coupling coefficient, an efficient filter may be designed and constructed. The component may be used in passive devices such as add-drop multiplexers or sensors, or in active devices such as lasers. Designs having essentially no response sidelobes, very narrow effective bandwidths, and fast filter roll-offs may permit compact devices to be produced, when compared with typical distributed sampled Bragg grating structures.
1. A device, comprising:
an optical ring waveguide having a grating along at least a portion thereof, and
an optical waveguide coupled to the optical ring waveguide,
wherein at least one of a reflection spectrum or a transmission spectrum of the device is determined by a circumference of the optical ring waveguide and at least one of a reflection spectrum or a transmission spectrum of the grating.
2. The device of claim 1 , wherein the optical ring waveguide has an optically active portion.
3. The device of claim 1 , wherein the optical ring waveguide is coupled to an active optical device.
4. The device of claim 1 , further comprising an active optical device inserted in the optical ring waveguide.
5. The device of claim 4 , wherein the active optical device is a semiconductor device.
6. The device of claim 3 , wherein the active optical device is coupled to the optical ring waveguide by insertion in the optical waveguide.
7. The device of claim 1 , wherein the circumference of the ring is an integral multiple of a refractive index periodicity of the grating.
8. The device of claim 1 , further comprising an etalon inserted in the ring.
9. The device of claim 8 , wherein the etalon is a Fabry-Perot interferometer.
10. The device of claim 1 , wherein the grating is formed by a plurality of spaced regions having at least one of a higher or a lower refractive index when compared with the refractive index of the optical ring waveguide.
11. The device of claim 1 , wherein the grating is formed by a plurality of perturbations spaced apart along a circumference of optical ring waveguide.
12. The device of claim 11 , where the spacing between the perturbations is uniform.
13. The device of claim 11 , wherein the spacing between the perturbations is selected to result in a Bragg grating.
14. The device of claim 11 , wherein the spacing between the perturbations is selected to result in a chirped grating.
15. The device of claim 1 , wherein the optical ring waveguide is a circle shape.
16. The device of claim 1 , wherein the optical ring waveguide is a racetrack shape.
17. The device of claim 1 , wherein a radius of curvature of the optical ring waveguide is large with respect to a design wavelength.
18. The device of claim 1 , wherein the optical ring waveguide has a transverse dimension suitable for single-mode optical transmission at a design wavelength.
19. The device of claim 1 , wherein the grating extends over half of the circumference of the optical ring waveguide.
20. The device of claim 1 , wherein the grating extends over the circumference of the optical ring waveguide.
21. An add-drop multiplexer, comprising:
an optical ring waveguide having a grating along at least a portion thereof;
a first optical waveguide coupled to the optical ring waveguide; and
a second optical waveguide coupled to the optical ring waveguide,
wherein an add-drop wavelength is determined by a diameter of the optical ring waveguide and a period of the grating.
22. The add-drop multiplexer of claim 21 , wherein an etalon is formed in the optical ring waveguide.
23. The add-drop multiplexer of claim 21 , wherein the grating has a length equal to one of half of or the full length of the optical ring waveguide.