Patent ID: 9562852
Date: 2017-02-07
CPC Classifications: G01J,G01N,G02B

Claim:
1. A gas sensor fabricated on a substrate that includes optical and electronic components, the sensor comprising: a laser configured to output light in a range of wavelengths within a waveguide; a splitter configured to split the light output by the laser to a reference waveguide and to a detection waveguide; the reference waveguide configured to expose the light to a reference gas and output a reference light, wherein the reference light exhibits a change in intensity from the light at wavelengths corresponding with an absorption spectrum of the reference gas; a reference cell configured to hermetically seal the reference gas and house the reference waveguide, the reference cell including back-end layers that include electrical circuits, a dielectric layer that is transparent to the light, and a sealing liner over the back-end layers, a volume of the reference cell being defined by a thickness of the back-end layers and a thickness of the dielectric layer; the detection waveguide configured to expose the light to ambient gas; and first and second optical detectors configured to receive light output from the reference waveguide and the detection waveguide, respectively, wherein the laser and the first and second optical detectors are arranged on a III-V die, the ambient gas is identified based on outputs of the first detector and the second detector, and the laser is tuned based on an absorption wavelength of the reference gas.