Abstract: An electronic device may have optical sensors. Control circuitry may use sensor measurements in controlling adjustable components and taking other actions. The optical sensors may be self-mixing sensors such as incoherent self-mixing sensors. One or more sensors may be used in gathering sensor measurements. In configurations in which an electronic device contain multiple self-mixing sensors, multi-wavelength measurements can be gathered using incoherent light sources in the sensors that operate a set of different wavelengths. The light source of each incoherent self-mixing sensor may be a superluminescent light-emitting diode, a resonant cavity light-emitting diode, or other amplified or non-amplified spontaneous emission source. Optical systems such as lenses in a housing for an electronic device may be aligned with the self-mixing sensors.

Abstract: A wearable electronic device including a housing that is worn by a user and a SMI sensor contained within the housing. The SMI sensor may include an emitter that outputs coherent light toward the skin of a user when the housing is worn by the user. The SMI sensor may also include a detector that detects a portion of the coherent light reflected towards the sensor and generates electrical signals that indicate displacements of the skin based on the portion of coherent light received at the detector. The housing may include a transmitter that is operatively coupled with the SMI sensor and is configured to transmit physiological data to a receiving device based on electrical signals output from the SMI sensor.

Abstract: A device includes a first component, a second component having a reconfigurable distance from the first component, an optical element, an SMI sensor, and a processor. The optical element has a fixed relationship with respect to the first component, and has a known optical thickness between a first surface and a second surface of the optical element. The SMI sensor has a fixed relationship with respect to the second component, and has an electromagnetic radiation emission axis that intersects the first and second surfaces of the optical element. The processor is configured to identify disturbances in an SMI signal generated by the SMI sensor, relate the disturbances to the known optical thickness of the optical element, and to determine a distance between the first and second components using the SMI signal and the relationship of the disturbances to the known optical thickness of the optical element.

Abstract: Aspects of the subject technology relate to an apparatus for self-mixing particulate-matter sensing using a vertical-cavity surface-emitting laser (VCSEL) with extrinsic photodiodes. The apparatus includes a dual-emitting light source disposed on a first chip and to generate a first light beam and a second light beam. The first light beam illuminates a particulate matter (PM), and a light detector extrinsic to the first chip measures the second light beam and variations of the second light beam and generates a self-mixing signal. The variations of the second light beam are caused by a back-scattered light resulting from back-scattering of the first light beam from the PM. The light detector is coupled to the dual-emitting light source. The direction of the second light beam is opposite to the direction of the first light beam, and the second light beam is directed to a sensitive area of the light detector.

Abstract: A wearable device includes a device housing configured to be worn on a first surface of a user, a set of one or more SMI sensors, and a processor. The set of one or more SMI sensors is mounted within the device housing and configured to emit a set of one or more beams of electromagnetic radiation, with each beam emitted in a different direction extending away from the first surface. The set of one or more SMI sensors is also configured to generate a set of one or more SMI signals containing information about a relationship between the device housing and a second surface. The processor is configured to extract the relationship between the device housing and the second surface from digitized samples of the set of one or more SMI signals.

Abstract: Disclosed herein are structures, devices, and systems for detecting touch and force inputs at multiple sensing locations on a surface of an electronic device using waveguide-based interferometry. A laser light source, such as a VCSEL, inserts light into a waveguide positioned adjacent to the sensing locations, and an input at a sensing location alters the inserted light in the waveguide allowing for determination of the input's touch or force at the sensing location. Wavelength modulation of the inserted light allows isolation in frequency of the signals from each sensing location. Optical phase locking can be used to lock an absolute distance beat frequency corresponding to a stationary reference point in the waveguide.

Abstract: An input device includes an enclosure defining a three-dimensional input space and one or more self-mixing interferometry sensors coupled to the enclosure and configured to produce a self-mixing interferometry signal resulting from reflection of backscatter of emitted light by a body part in the three-dimensional input space. In various examples, movement of the body part may be determined using the self-mixing interferometry signal, which may in turn be used to determine an input. In some examples, a body part displacement or a body part speed and an absolute distance to the body part may be determined using the self-mixing interferometry signal and used to determine an input. In a number of examples, multiple self-mixing interferometry sensors may be used and the movement may be determined by analyzing differences between the respective produced self-mixing interferometry signals.

Abstract: A device includes an electronic display, a cover through which the electronic display projects an image, and an array of SMI sensors. The array of SMI sensors is positioned on a same side of the cover as the electronic display. Each SMI sensor is configured to emit electromagnetic radiation toward a respective portion of: an interior surface of the cover, or a surface of a component of the device attached to the cover; and generate a respective SMI output including information indicative of vibration of the respective portion of the cover or the component. The device also includes circuitry configured to characterize a vibratory waveform impinging on the device. The vibratory waveform is characterized using at least two of the SMI outputs.

Abstract: Disclosed herein are electronic devices, and methods for their operation, that identify user inputs based on interaction of an object with input surfaces separate from the electronic devices. The electronic devices may include one or more self-mixing interferometry sensors that scan a field of view containing the input surface with a light beam, such as a laser beam emitted laser diode. Self-mixing of the emitted light with reflections can generate a self-mixing interferometry signal. Analysis of the self-mixing interferometry signal can allow for identification of an object, such as a user's finger, in the field of view. Deformation of the finger can be detected with the self-mixing interferometry sensor, and a user input identified therefrom.

Abstract: Disclosed herein are wearable devices, their configurations, and methods of operation that use self-mixing interferometry signals of a self-mixing interferometry sensor to recognize user inputs. The user inputs may include voiced commands or silent gesture commands. The devices may be wearable on the user's head, with the self-mixing interferometry sensor configured to direct a beam of light toward a location on the user's head. Skin deformations or vibrations at the location may be caused by the user's speech or the user's silent gestures and recognized using the self-mixing interferometry signal. The self-mixing interferometry signals may be used for bioauthentication and/or audio conditioning of received sound or voice inputs to a microphone.

Abstract: An optical sensing system can be integrated into a camera module. In particular, an optical element of an optical sensing system can be disposed entirely or partly within a barrel of a camera module. The optical element can be oriented toward a reflective surface, such as an infrared cut filter, such that an optical path is defined between free space and the optical element via at least one reflection off the reflective surface.

Abstract: Disclosed herein are electronic devices, and methods for their operation, that identify user inputs based on interaction of an object with input surfaces separate from the electronic devices. The electronic devices may include one or more self-mixing interferometry sensors that scan a field of view containing the input surface with a light beam, such as a laser beam emitted laser diode. Self-mixing of the emitted light with reflections can generate a self-mixing interferometry signal. Analysis of the self-mixing interferometry signal can allow for identification of an object, such as a user's finger, in the field of view. Deformation of the finger can be detected with the self-mixing interferometry sensor, and a user input identified therefrom.

Abstract: Disclosed herein are structures, devices, and systems for detecting touch and force inputs at multiple sensing locations on a surface of an electronic device using waveguide-based interferometry. A laser light source, such as a VCSEL, inserts light into a waveguide positioned adjacent to the sensing locations, and an input at a sensing location alters the inserted light in the waveguide allowing for determination of the input's touch or force at the sensing location. Wavelength modulation of the inserted light allows isolation in frequency of the signals from each sensing location. Optical phase locking can be used to lock an absolute distance beat frequency corresponding to a stationary reference point in the waveguide.

Abstract: Various sensors, including particulate matter sensors, are described. One particulate matter sensor includes a self-mixing interferometry sensor and a set of one or more optical elements. The set of one or more optical elements is positioned to receive an optical emission of the self-mixing interferometry sensor, split the optical emission into multiple beams, and direct each beam of the multiple beams in a different direction. The self-mixing interferometry sensor is configured to generate particle speed information for particles passing through respective measurement regions of the multiple beams.

Abstract: A portable electronic device is operable in a particulate matter concentration mode where the portable electronic device uses a self-mixing interferometry sensor to emit a beam of coherent light from an optical resonant cavity, receive a reflection or backscatter of the beam into the optical resonant cavity, produce a self-mixing signal resulting from a reflection or backscatter of the beam of coherent light, and determine a particle velocity and/or particulate matter concentration using the self-mixing signal. The portable electronic device is also operable in an absolute distance mode where the portable electronic device determines whether or not an absolute distance determined using the self-mixing signal is outside or within a particulate sensing volume associated with the beam of coherent light. If not, the portable electronic device may determine a contamination and/or obstruction is present that may result in inaccurate particle velocity and/or particulate matter concentration determination.

Abstract: Aspects of the subject technology relate to particulate matter sensors for electronic devices. A particulate matter sensor may include three lasers, three total-internal-reflection lenses, and three detectors for detecting changes in the operation of the three lasers due to the principles of self-mixing interferometry. The three total-internal-reflection lenses may use internally reflective surfaces to tilt the three beams into three corresponding directions that form an orthogonal basis in the three dimensional space, so that a gas flow speed can be determined while maintaining a small, modular form factor for implementation of the sensor in portable electronic devices.

Abstract: An electronic device such as an earbud may have control circuitry mounted in a housing. The housing may have portions such as an ear portion with a speaker port through which a speaker plays audio and a stalk portion that extends from the ear portion. Proximity sensors may be formed in the electronic device. For example, one or more proximity sensors may be formed on the ear portion to detect when a user has inserted an earbud into the ear of the user and/or one or more proximity sensors may be formed on a stalk portion to detect when a user is holding an earbud by the stalk or when a user is providing finger touch input such as taps, swipes, and/or other gestures on the stalk portion. The proximity sensors may be optical proximity sensors such as coherent self-mixing proximity sensors.

Abstract: A portable communication device includes one or more optical detectors to generate an analog signal in response to a change in an intra-cavity or an emitted optical power of a light source due to light backscattered from a particle and an application-specific integrated circuit (ASIC). The particle is illuminated via a light source. The ASIC includes an analog-to-digital converter (ADC) circuit, a digital delay circuit, a particle detector module and a processor. The ADC converts the analog signal to a digital signal. The digital delay circuit can store the digital signal for a predetermined or dynamically variable time interval. The particle detector module can analyze the digital signal and can generate an enable signal upon detecting a particle signature in the digital signal. The processor is coupled to the digital delay circuit and can start processing the digital signal in response to the enable signal.

Abstract: Disclosed herein are structures, devices, and systems for detecting touch and force inputs at multiple sensing locations on a surface of an electronic device using waveguide-based interferometry. A laser light source, such as a VCSEL, inserts light into a waveguide positioned adjacent to the sensing locations, and an input at a sensing location alters the inserted light in the waveguide allowing for determination of the input's touch or force at the sensing location. Wavelength modulation of the inserted light allows isolation in frequency of the signals from each sensing location. Optical phase locking can be used to lock an absolute distance beat frequency corresponding to a stationary reference point in the waveguide.

Abstract: Disclosed herein are structures, devices, and systems for detecting touch and force inputs at multiple sensing locations on a surface of an electronic device using waveguide-based interferometry. A laser light source, such as a VCSEL, inserts light into a waveguide positioned adjacent to the sensing locations, and an input at a sensing location alters the inserted light in the waveguide allowing for determination of the input's touch or force at the sensing location. Wavelength modulation of the inserted light allows isolation in frequency of the signals from each sensing location. Optical phase locking can be used to lock an absolute distance beat frequency corresponding to a stationary reference point in the waveguide.