Patent ID: 11874110
Assignee: APPLE INC.
Field: Measurement (Instruments)
Classification: CPC G  A | IPC G

Claim 8:
9. An electronic device for performing non-reciprocal self- mixing interferometry, the electronic device comprising:
a self-mixing interferometry sensor configured to emit a beam of light; and
a birefringent circulator positioned in an illumination path of the emitted beam of light and in a collection path of a returned portion of the beam of light, the birefringent circulator configured to direct the beam of light emitted from the self-mixing interferometry sensor from a first aperture of the birefringent circulator, the birefringent circulator comprising:
a Faraday rotator; and
a wave plate, wherein the Faraday rotator and the wave plate are configured to transform a first polarization of the beam of light into a second polarization as the beam of light travels along the illumination path, wherein:

the birefringent circulator directs the returned portion of the beam of light, received from a second aperture of the birefringent circulator, into the self-mixing interferometry sensor.