Near-infrared laser diodes used in imaging applications

A wearable device, comprising:

• a measurement device to measure a physiological parameter adapted to be placed on a wrist or an ear of a user, comprising at least a first light emitting diode and a second light emitting diode, the first light emitting diode configured to generate a first output optical beam, the first output optical beam having an initial light intensity and at least one near-infrared wavelength between 700 nanometers and 2500 nanometers, the second light emitting diode configured to generate a second output optical beam, the second output optical beam having an initial light intensity and at least one near-infrared wavelength between 700 nanometers and 2500 nanometers;
• the measurement device further comprising a receiver, the receiver having a first detector and a second detector, the first and second detectors being spatially separated, the first detector configured to receive at least a first reflected portion of the first output optical beam, the second detector configured to receive at least a first reflected portion of the second output optical beam;
• one or more analog to digital converters coupled to the spatially separated detectors and configured to generate a first detector signal representing at least in part the first reflected portion of the first output optical beam and to generate a second detector signal representing at least in part the first reflected portion of the second output optical beam, and wherein the receiver is configured to generate an output signal at least in part by comparing the first detector signal and the second detector signal;
• the measurement device configured to improve signal-to-noise ratio of the output signal by increasing light intensity relative to the initial light intensity of at least the first light emitting diode;
• wherein the measurement of the physiological parameter is at least in part a non-invasive measurement on blood;
• and
• wherein the receiver is configured to synchronize to at least one of the first and second light emitting diodes.

A wearable device, comprising:

• a measurement device to measure a physiological parameter adapted to be placed on a wrist or an ear of a user comprising at least a first light emitting diode and a second light emitting diode, the first light emitting diode configured to generate a first optical beam, the first optical beam having an initial light intensity and at least one near-infrared wavelength between 700 nanometers and 2500 nanometers, the second light emitting diode configured to generate a second optical beam, the second optical beam having an initial light intensity and at least one near-infrared wavelength between 700 nanometers and 2500 nanometers;
• the measurement device configured to output at least a portion of the first optical beam as a first output optical beam, and to output at least a portion of the second optical beam as a second output optical beam;
• the measurement device further comprising a receiver having one or more detectors, wherein one of the one or more detectors is located a first distance from the first light emitting diode and a different distance from the second light emitting diode to be capable of receiving at least a first reflected portion of the first output optical beam and generating a first detector signal, and receiving at least a first reflected portion of the second output optical beam and generating a second detector signal;
• wherein the receiver is configured to generate an output signal in part by comparing the first detector signal and the second detector signal;
• the measurement device configured to improve signal-to-noise ratio of the output signal by increasing light intensity relative to the initial light intensity of at least the first light emitting diode;
• wherein the measurement of the physiological parameter is at least in part a non-invasive measurement on blood;
• and
• wherein the receiver is configured to lock-in to at least one of the first and second light emitting diodes.

A wearable device, comprising:

• a measurement device to measure a physiological parameter adapted to be placed on a wrist or an ear of a user, comprising at least a first light emitting diode and a second light emitting diode, the first light emitting diode configured to generate a first optical beam, the first optical beam having an initial light intensity and at least one near-infrared wavelength between 700 nanometers and 2500 nanometers, the second light emitting diode configured to generate a second optical beam, the second optical beam having an initial light intensity and at least one near infrared wavelength between 700 nanometers and 2500 nanometers;
• the measurement device configured to output at least a portion of the first optical beam as a first output optical beam, and to output at least a portion of the second optical beam as a second output optical beam;
• the measurement device further comprising a receiver having a first detector and a second detector, the first and second detectors being spatially separated, the first detector configured to receive at least a first reflected portion of the first output optical beam and to generate a first detector signal in response, the second detector configured to receive at least a first reflected portion of the second output optical beam and to generate a second detector signal in response;
• wherein at least one of the first and second detectors is located a first distance from the first light emitting diode and a different distance from the second light emitting diode and configured to receive at least a second reflected portion of the first output optical beam and to generate a third detector signal in response, and configured to receive at least a second reflected portion of the second output optical beam and to generate a fourth detector signal in response;
• the measurement device configured to generate an output signal representing at least in part a non-invasive measurement on blood, the output signal generated at least in part by comparing the first detector signal with the second detector signal, and comparing the third detector signal with the fourth detector signal;
• the measurement device further configured to improve the signal-to-noise ratio of the output signal by increasing light intensity relative to the initial light intensity of at least the first light emitting diode;
• wherein the first and second light emitting diodes operate in a continuous wave operation mode or a pulsed operation mode;
• and
• wherein the receiver is configured to synchronize with the operation mode of at least one of the first and second light emitting diodes.