Laser with resonant reflector
View Patent ↗A vertical cavity surface-emitting laser (VCSEL) is disclosed. The VCSEL includes a layer that at least partially defines an optical cavity having an optical axis. The VCSEL further includes a resonant reflector layer extending across at least part of the optical cavity. The resonant reflector layer has a refractive index that does not abruptly change laterally across the optical cavity. The refractive index of the resonant reflector layer includes contributions from a first material having a first refractive index and a second material having a second refractive index. At least one of the first material and the second material includes a polymer.
1. A vertical cavity surface-emitting laser (VCSEL), comprising:
a plurality of layers that at least partially define an optical cavity having an optical axis, the plurality of layers including a top mirror layer; and
a resonant reflector layer adjacent the top mirror layer and configured to reduce a lateral mode of the optical cavity, the resonant reflector extending across at least part of the optical cavity, the resonant reflector layer having a refractive index that does not abruptly change laterally across the optical cavity, the refractive index of the resonant reflector layer including contributions from a first material having a first refractive index and a second material having a second refractive index, at least one of the first material and the second material comprising a polymer having a refractive index that is less than a refractive index of the top mirror layer.
2. The VCSEL as recited in claim 1 , wherein the first material is substantially confined to a first region and the second material is substantially confined to a second region, the first region and the second region co-extending along an interface, at least part of the interface being non-parallel with respect to the optical axis.
3. The VCSEL as recited in claim 2 , wherein the first region is positioned proximate a center of the optical cavity and includes lateral edges that are non-parallel with respect to the optical axis, and the second region includes lateral edges that co-extend along the lateral edges of the first region.
4. The VCSEL as recited in claim 3 , wherein the lateral edges of the first region are at least partially curved.
5. The VCSEL as recited in claim 3 , wherein the lateral edges of the first region are at least partially tapered.
6. The VCSEL as recited in claim 1 , wherein the first refractive index is less than the second refractive index.
7. The VCSEL as recited in claim 1 , wherein the first material substantially comprises AlGaAs, and the second material substantially comprises a polymer.
8. The VCSEL as recited in claim 7 , wherein the polymer substantially comprises one of: polyimide; or, benzocyclobuthene (BCB).
9. The VCSEL as recited in claim 1 , wherein a reflectivity of the resonant reflector is at a maximum in a location proximate a center of the optical cavity.
10. The VCSEL as recited in claim 1 , wherein a reflectivity of the resonant reflector is substantially symmetric about a center of the optical cavity.
11. The VCSEL as recited in claim 1 , further comprising an additional layer disposed on top of the resonant reflector, the additional layer comprising one of: at least one period of a semiconductor DBR mirror; or, a narrow band dielectric reflection filter.
12. The VCSEL as recited in claim 1 , further comprising a contact layer arranged proximate a periphery of the optical cavity.
13. The VCSEL as recited in claim 1 , wherein the top mirror layer has a refractive index that is greater than the first refractive index and the second refractive index.
14. The VCSEL as recited in claim 1 , wherein the top mirror layer substantially comprises AlGaAs.
15. The VCSEL as recited in claim 1 , wherein the polymer is a non-conductive material.