Surface emitting photonic device
View Patent ↗A surface emitting photonic device including a substrate; and a waveguide structure on the substrate. The waveguide structure includes an active region along its longitudinal axis and the active region is for generating light. The waveguide structure also has a trench formed therein transverse to the active region and defining a first wall forming an angled facet at one end of the active region, the first wall having a normal that is at a non-parallel angle relative to the longitudinal axis of the waveguide structure. The trench also defines a second wall located opposite the first wall.
1. A method for fabricating a surface emitting photonic device, said method comprising:
forming a waveguide structure on a substrate, the waveguide structure having an active region along a longitudinal axis of the waveguide structure; and
etching the waveguide structure to form a trench transverse to and intersecting the active region in the waveguide structure, a first side of the trench forming an angled facet at one location along the waveguide structure and a second side of the trench forming a wall at a second location along the waveguide structure, said angled facet having a normal that is at a non-parallel angle relative to the longitudinal axis, wherein the active region is interrupted by the trench between the first and second sides of the trench.
2. The method of claim 1 , wherein the trench is no greater than 8 μm across as measured from the first side to the second side.
3. The method of claim 1 , wherein the trench is no greater than 4 μm across as measured from the first side to the second side.
4. The method of claim 1 , wherein the trench is no greater than 1 μm across as measured from the first side to the second side.
5. The method of claim 1 , wherein forming the waveguide structure comprises depositing an epitaxial semiconductor.
6. The method of claim 5 , wherein the normal of the angled facet is at an angle of about 44.4°±1° relative to the longitudinal axis.
7. The method of claim 1 , wherein the normal of the angled facet is such as to cause an electromagnetic wave generated during operation to be internally reflected and emitted in a direction that is away from and substantially perpendicular to the substrate.
8. The method of claim 1 , wherein forming the waveguide structure comprises depositing multiple layers on a top surface of the substrate and wherein the active region is substantially parallel to a top surface of the substrate.
9. The method of claim 8 , further comprising depositing electrodes on the waveguide structure and the substrate for receiving a bias voltage to activate the waveguide structure to generate a laser output beam.
10. The method of claim 9 , wherein forming the waveguide structure further comprises etching the multiple layers on the top surface of the substrate to form a ridge for a ridge laser.
11. The method of claim 1 , wherein etching the waveguide structure to form the trench produces an etched base within the trench.
12. The method of claim 11 , wherein the etched base contains at least a portion that is parallel to the longitudinal axis.
13. The method of claim 11 , wherein the etched base contains at least a portion that is rounded.
14. The method of claim 1 , wherein the wall at the second location has a normal that is substantially parallel to the longitudinal axis.
15. The method of claim 1 , further comprising etching the waveguide structure to form an end facet, wherein the end facet and the angled facet define a cavity of a laser.
16. The method of claim 15 , wherein the end facet has a normal that is essentially parallel to a plane of the active layer.
17. The method of claim 16 , wherein the normal of the end facet is essentially parallel to the longitudinal axis of the waveguide structure.
18. The method of claim 17 , further comprising coating the end facet with a reflectivity modification layer or stack.
19. The method of claim 15 , wherein the end facet has a normal that is not parallel to the longitudinal axis.
20. The method of claim 19 , further comprising coating the region above the end facet with reflectivity modification layer or stack.