Patent ID: 11909171
Assignee: APPLE INC.
Field: Measurement (Instruments)
Classification: CPC H  G | IPC G  H

Claim 7:
8. An optical sensor system, comprising:
a substrate;
a first photodetector on the substrate;
a second photodetector on the substrate, laterally offset from the first photodetector;
an epitaxial stack;
a semiconductor laser formed in an epitaxial stack, the epitaxial stack attached to the substrate, the semiconductor laser aligned with the first photodetector and configured to make a first emission of electromagnetic radiation toward the first photodetector, the semiconductor laser having a resonant cavity in which emitted electromagnetic radiation and returned electromagnetic radiation is self-mixed;
an optical subsystem configured to,
receive a second emission of the semiconductor laser; and
redirect a portion of the second emission toward the second photodetector; and

a noise-mitigating self-mixing interferometry (SMI) signal channel configured to combine a first photocurrent from the first photodetector and a second photocurrent from the second photodetector; wherein,
the first photodetector is outside of the epitaxial stack.