Claims
- 1. A method of improving selectivity in a tunable waveguide filter that includes first and second waveguides, the first waveguide being a semi-active waveguide, the method comprising:
coupling light between the first and second waveguides; passing current through the first and second waveguides to tune a light frequency of maximum transmission through the filter; and amplifying the light in the semi-active waveguide.
- 2. A method as recited in claim 1, wherein optical gain in the semi-active waveguide substantially compensates for losses arising from the current passing through the semi-active waveguide.
- 3. A method as recited to claim 1, wherein the semi-active waveguide has a bandgap energy close to the photon energy of the light coupled between the first and second waveguides.
- 4. A method as recited in claim 3, wherein the bandgap energy is greater than the photon energy.
- 5. A method as recited in claim 1, wherein the semi-active waveguide is formed from In(1-x)GaxAsP(1-y).
- 6. A method as recited in claim 5, wherein X has a value of approximately 40% and Y has a value of approximately 80%.
- 7. A tunable filter, comprising:
a first waveguide; a second waveguide proximate the first waveguide so that light couples between the first and second waveguides, the second waveguide being semi-active; and a grating structure disposed proximate at least one of the first and second waveguides to enhance coupling of light between the first and second waveguides.
- 8. A filter as recited in claim 7, wherein optical gain in the semi-active waveguide substantially compensates for filter losses arising from a tuning current passing through the semi-active waveguide.
- 9. A filter as recited to claim 7, wherein the semi-active waveguide has a bandgap energy close to the photon energy of the light coupled between the two waveguides.
- 10. A filter as recited in claim 9, wherein the bandgap energy is greater than the photon energy.
- 11. A filter as recited in claim 7, wherein the semi-active waveguide is formed from In(1-x)GaxAsP(1-y).
- 12. A filter as recited in claim 11, wherein X has a value of approximately 40% and Y has a value of approximately 80%.
- 13. A filter as recited in claim 7, wherein the filter has a first transmission spectrum associated with a first optical center frequency when no current passes through the filter and a second spectrum associated with a second optical center frequency when a tuning current passes through the filter.
Priority Claims (1)
Number |
Date |
Country |
Kind |
0100610-5 |
Feb 2001 |
SE |
|
Parent Case Info
[0001] This application claims priority from Swedish patent application 01006105, filed on Feb. 22, 2001, which is incorporated herein by reference.