Self-mixing interference device for sensing applications

A self-mixing interferometry (SMI) sensor, comprising:

• a first set of semiconductor layers formed on a substrate, wherein the first set of semiconductor layers include a first active region layer positioned between a first emission side distributed Bragg reflector and a first base side distributed Bragg reflector;
• a vertical cavity surface emitting laser (VCSEL) diode comprising a second set of semiconductor layers formed on the first set of semiconductor layers, wherein the second set of semiconductor layers include a second active region layer positioned between a second emission side distributed Bragg reflector and the second base side distributed Bragg reflector;
• and
• a third set of semiconductor layers formed on the substrate and positioned laterally adjacent to the first set of semiconductor layers.

A self-mixing interferometry (SMI) sensor, comprising:

• a resonant cavity photodetector (RCPD) comprising a first set of semiconductor layers formed on a substrate;
• and
• a vertical cavity surface emitting laser (VCSEL) diode formed over the RCPD and comprising a second set of semiconductor layers formed on the first set of semiconductor layers;
• and
• an etch stop layer between the first set of semiconductor layers and the second set of semiconductor layers;
• wherein:
• the VCSEL diode is configured to emit laser light when forward biased and undergo self-mixing interference upon reception of reflections or backscatters of the emitted laser light from an object, the self-mixing interference altering a property of the emitted laser light;
• and
• the RCPD is configured to be reverse biased during emission of the laser light by the VCSEL diode and detect an alteration in the property of the emitted laser light.