In situ calibration of a light source in a sensor device
| DWPI Title: Sensor device has microscale light source that emits monochromatic optical signal, and calibration system that facilitates in situ calibration of light source to mitigate drift from constant wavelength |
| Abstract: A sensor device is described herein, wherein the sensor device includes an optical measurement system, such as an interferometer. The sensor device further includes a low-power light source that is configured to emit an optical signal having a constant wavelength, wherein accuracy of a measurement output by the sensor device is dependent upon the optical signal having the constant wavelength. At least a portion of the optical signal is directed to a vapor cell, the vapor cell including an atomic species that absorbs light having the constant wavelength. A photodetector captures light that exits the vapor cell, and generates an electrical signal that is indicative of intensity of the light that exits the vapor cell. A control circuit controls operation of the light source based upon the electrical signal, such that the light source emits the optical signal with the constant wavelength. |
| Use: Sensor device. Uses include but are not limited to thermometer, microphone, magnetometer, accelerometer, gyroscope, seismometer, or gravimeter. |
| Advantage: The relatively small size of the light source and the calibration system allows integration into the sensor device. Reduces power consumed by the light source by using a microscale light source, such as a vertical-cavity surface-emitting laser (VCSEL). Enables detection of changes in frequency and/or changes in amplitude of the optical signal emitted by the light source, and can correct a measurement signal output by the interferometer based upon the detected changes in frequency and/or changes in amplitude. |
| Novelty: The sensor device has an interferometer (102), a microscale light source (104) that emits a monochromatic optical signal, and a calibration system (106) that facilitates in situ calibration of the microscale light source to mitigate drift from constant wavelength. The calibration system includes a photodetector (216,220) which captures light that exits a vapor cell, and generates electrical signal that is indicative of light intensity, and a circuit (222) which controls operation of light source based on electrical signal, such that light source emits optical signal with constant wavelength. |
| Filed: 9/19/2013 |
| Application Number: US14031863A |
| Tech ID: SD 12044.0 |
| This invention was made with Government support under Contract No. DE-NA0003525 awarded by the United States Department of Energy/National Nuclear Security Administration. The Government has certain rights in the invention. |
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