Methods for producing a tunable vertical cavity surface emitting laser
View Patent ↗Methods are disclosed for producing a tunable vertical cavity surface emitting laser (VCSEL) using photonic crystals and an electrostrictive material that includes a hologram with a narrow filter function. Photonic crystals are formed such that the active region of the VCSEL is bounded by the photonic crystals. The photonic crystals have a periodic cavity structure that reflects light of certain wavelengths through the active region of the VCSEL such that laser light at the wavelengths is generated. The periodic cavity structure includes a central defect that does not include any cavities. The single mode is emitted through the central defect. The electrostrictive material that includes a hologram makes the VCSEL tunable because the shape of the electrostrictive material changes when an electric field is applied. The filter function of the hologram thus changes as well in response to the electric field such that the VCSEL is tunable.
1. A method for producing a tunable vertical cavity surface emitting laser, the method comprising:
providing a substrate;
creating a first plurality of DBR layers on the substrate;
creating an active region on one of the first plurality of DBR layers, the active region comprising at least one quantum well layer and at least one quantum well barrier layer;
forming a plurality of semi-insulating regions in the active region that extend vertically through the at least one quantum well layer;
creating a second plurality of DBR layers on the active region; and
forming a photonic crystal comprising a plurality of cavities, each of the plurality of cavities passing through the first and second plurality of DBR layers as well as through a corresponding semi-insulating region of the active region.
2. The method as recited in claim 1 , further comprising filling at least some of the cavities of the photonic crystal.
3. The method as recited in claim 2 , wherein filling at least some of the cavities of the photonic crystal comprises filling at least some of the cavities with a tunable material.
4. The method as recited in claim 2 , wherein filling at least some of the cavities of the photonic crystal comprises filling at least some of the cavities with one or more of dielectric material; Al; In; Ga; As; Sb; and, N.
5. The method as recited in claim 1 , wherein each of the cavities is defined such that the portion of the cavity passing through the corresponding semi-insulating region is surrounded by semi-insulating material.
6. The method as recited in claim 1 , wherein the semi-insulating material comprises FeInP.
7. The method as recited in claim 1 , wherein a depth of each semi-insulating region is substantially coextensive with a thickness of the active region.
8. The method as recited in claim 1 , wherein the plurality of cavities are formed by drilling.
9. The method as recited in claim 1 , wherein the plurality of cavities at least partially defines boundaries of a central defect in each of the first plurality of DBR layers and the second plurality of DBR layers.
10. The method as recited in claim 9 , wherein the central defect comprises a portion of the photonic crystal free of cavities.
11. The method as recited in claim 1 , wherein the plurality of cavities is defined such that a periodic structure is formed in each of the first plurality of DBR layers and the second plurality of DBR layers.
12. The method as recited in claim 11 , wherein the periodic structure is formed such that the photonic crystal is reflective for at least one selected wavelength.
13. The method as recited in claim 1 , wherein the plurality of cavities of the photonic crystal are formed through the semi-insulating regions such that the active region includes a lattice structure of semi-insulating rings.
14. The method as recited in claim 1 , further comprising creating a tunable element on one of the second plurality of DBR layers.
15. The method as recited in claim 14 , wherein creating a tunable element comprises creating an electrostrictive polymer filter including one of: a reflection hologram; or, a holographic optical element (HOE).
16. The method as recited in claim 14 , further comprising forming a contact on the tunable element.
17. The method as recited in claim 14 , wherein creation of the tunable element occurs subsequent to definition of the plurality of cavities.
18. The method as recited in claim 14 , wherein the tunable element has a tuning range of at least 40 nm.
19. A tunable vertical cavity surface emitting laser manufactured according to the method of claim 1 .