Long wavelength vertical cavity surface emitting laser
View Patent ↗Selectively oxidized vertical cavity lasers emitting near 1300 nm using InGaAsN quantum wells are reported for the first time which operate continuous wave below, at and above room temperature. The lasers employ two n-type Al 0.94 Ga 0.06 As/GaAs distributed Bragg reflectors each with a selectively oxidized current aperture adjacent to the active region, and the top output mirror contains a tunnel junction to inject holes into the active region. Continuous wave single mode lasing is observed up to 55° C.
1. A vertical cavity surface emitting laser comprising:
a substrate;
a first n-type mirror adjacent the substrate;
an active region including one or more quantum wells, the quantum wells being formed of InGaAsN;
a second n-type mirror adjacent the active region, the second mirror including a tunnel junction for injecting holes into the active region,
wherein the laser emits light at a nominal wavelength of 1300 nm.
2. The vertical cavity surface emitting laser of claim 1 , wherein the substrate includes GaAs.
3. The vertical cavity surface emitting laser of claim 1 , wherein the tunnel junction includes a n-type layer and a p-type layer.
4. The vertical cavity surface emitting laser of claim 3 , wherein the p-type layer of the tunnel junction is positioned at or near a standing wave null in optical field.
5. The vertical cavity surface emitting laser of claim 2 , further comprising one or more oxide apertures, proximate to the active region, wherein the oxide aperture includes an oxidized portion therein.
6. The vertical cavity surface emitting laser of claim 5 wherein the oxidized portion of the oxide aperture comprises an aluminum oxide.
7. The vertical cavity surface emitting laser of claim 5 wherein the oxide aperture comprises a carbon doped spike positioned at or near a standing wave null in optical field.
8. The vertical cavity surface emitting laser of claim 5 , further comprising a mesa extending downward at least to the oxide aperture.
9. The vertical cavity surface emitting laser of claim 1 wherein the first and second n-type mirrors comprise unipolar distributed Bragg reflector mirrors.
10. The vertical cavity surface emitting laser of claim 1 further comprising an upper electrode above the second mirror stack and a lower electrode below the active region.
11. The vertical cavity surface emitting laser of claim 10 wherein the lower electrode includes an annular aperture therein to monitor transmitted output power of the vertical cavity surface emitting laser from light emitted through the annular aperture in the lower electrode.
12. A method of manufacturing a surface emitting laser that emits light at a nominal wavelength of 1300 nm., comprising:
forming a first n-type mirror on a substrate;
forming an active region having one or more InGaAsN quantum wells on the substrate;
forming a current constriction proximate the active region;
forming a second n-type mirror above the active region; and
forming a tunnel junction in the second n-type mirror, wherein the tunnel junction comprises an n-type region and a p-type region and the p-type region is positioned at or near a standing wave null in optical field.
13. The method of claim 12 wherein the step of forming a current constriction comprises forming oxide aperture layers proximate to said active region.
14. The method of claim 13 wherein the step of forming oxide aperture layers proximate to said active region comprises forming at least one aluminum alloy layer proximate to said active region.
15. The method of claim 14 further comprising forming a mesa downward from upper most surface of the surface emitting laser to the oxide aperture layers and oxidizing an annular portion of said oxide aperture layers.
16. The method of claim 14 wherein the step of forming oxide aperture layers further comprises doping each aluminum alloy layer with an n-type or p-type dopant.
17. The method of claim 16 wherein the step of doping the aluminum alloy layer with the p-type dopant further comprises forming a carbon doped spike in said aluminum alloy layer, wherein said carbon doped spike is positioned at or near a standing wave null in the optical field.
18. The method of claim 12 wherein the step of forming said second mirror comprises forming one or more pairs of semiconductor mirror layers, wherein one layer in each pair has an index of refraction that is different from the index of refraction of the layer in each pair.
19. The method of claim 18 wherein the step of forming said semiconductor mirror layers comprises forming one quarter wavelength thick alternating layers of AIGaAs and GaAs, wherein said tunnel junction is formed into the GaAs layer nearest said active region.
20. The method of claim 12 further comprising forming an upper electrode above the second mirror and forming a lower electrode below the active region.
21. The method of claim 20 wherein the steps of forming the upper and lower electrodes comprises forming at least one of the upper and lower electrodes having an annular aperture therein.