Horizontal cavity surface-emitting laser (HCSEL) monolithically integrated with a photodetector

An optoelectronic device, comprising:

• a semiconductor substrate;
• a laser, epitaxially grown on the semiconductor substrate and having a laser resonant cavity extending between a front side output surface parallel to the semiconductor substrate and a back side output surface perpendicular to the semiconductor substrate;
• a semiconductor device, epitaxially grown on the semiconductor substrate and separated from the back side output surface of the laser by a single trench having a first vertical wall abutting the laser and a second vertical wall abutting the semiconductor device;
• and
• at least two coatings comprising a first coating and a second coating, each of the first coating and the second coating on at least one of the first vertical wall or the second vertical wall, and only one of the first coating or the second coating extending over the front side output surface of the laser;
• wherein,
• the laser resonant cavity has a horizontal portion parallel to the semiconductor substrate;
• each of the first vertical wall and the second vertical wall is oriented perpendicular to the semiconductor substrate;
• and
• the first coating has a first reflectivity different from a second reflectivity of the second coating.

An electronic device, comprising:

• a housing;
• a cover mounted to the housing;
• a display positioned under the cover and viewable through the cover;
• a horizontal cavity surface-emitting laser (HCSEL) configured to emit infrared radiation through at least a primary emission facet at one end of the HCSEL and through the display and the cover;
• a semiconductor substrate on which the HCSEL is epitaxially grown;
• a photodetector, epitaxially grown on the semiconductor substrate and separated from the HCSEL by a trench;
• at least one first coating on at least one vertical wall of the trench and not extending over the primary emission facet;
• and
• at least one second coating on at least one vertical wall of the trench and extending over the primary emission facet;
• wherein,
• the at least one first coating has a first reflectivity different from a second reflectivity of the at least one second coating.