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

Claim 0:
1. An optical sensor system, comprising:
a semiconductor substrate;
a set of epitaxial layers formed on the semiconductor substrate and defining,
a semiconductor laser having a first multiple quantum well (MQW) structure, wherein electromagnetic radiation is generated by the first MQW structure, emitted from the first MQW structure, and self-mixed with a portion of the emitted electromagnetic radiation that is returned to the first MQW structure;
a second MQW structure, positioned on a first side of the first MQW structure and operable to generate a first photocurrent responsive to detecting a first emission of the semiconductor laser; and
a third MQW structure, positioned on a second side of the first MQW structure and operable to generate a second photocurrent responsive to detecting a second emission of the semiconductor laser, the second side opposite the first side; and

a circuit configured to generate a self-mixing interferometry (SMI) signal by combining the first photocurrent and the second photocurrent.