Systems and methods for wavelength locking in optical sensing systems
Disclosed herein is an integrated photonics device including a frequency stabilization subsystem for monitoring and/or adjusting the wavelength of light emitted by one or more light sources. The device can include one or more selectors that can combine, select, and/or filter light along one or more light paths, which can include light emitted by a plurality of light sources. Example selectors may include, but are not limited to, an arrayed waveguide grating (AWG), a ring resonator, a plurality of distributed Bragg reflectors (DBRs), a plurality of filters, and the like. Output light paths from the selector(s) can be input into one or more detector(s). The detector(s) can receive the light along the light paths and can generate one or more signals as output signal(s) from the frequency stabilization subsystem. A controller can monitor the wavelength and can adjust or generate control signal(s) for the one or more light sources to lock the monitored wavelength to a target wavelength (or within a targeted range of wavelengths).
1. A system comprising:
a light source that emits light along an input light path;
a selector comprising an arrayed waveguide grating configured to:
receive light along the input light path;
output light of a first wavelength along a first output of the arrayed waveguide grating;
output light of a second wavelength along a second output of the arrayed waveguide grating; and
output light along a third output of the arrayed waveguide grating;
a first detector that receives the output light of the first wavelength from the first output;
a second detector that receives the output light of the second wavelength from the second output; and
a controller that:
receives signals generated by the first detector and the second detector;
determines a ratio of the signals generated by the first detector and the second detector; and
generate a control signal for the light source based on the determined ratio, wherein the control signal controls the light source to lock a wavelength of light emitted by the light source along the third output to a target wavelength.
2. The system of claim 1 , comprising:
a plurality of light sources that includes the light source that emit light along a plurality of light paths that includes the input path, wherein the arrayed waveguide grating receives light from the plurality of light sources along the plurality of light paths.
3. The system of claim 1 , comprising:
a plurality of light sources that includes the light source that emit light along a plurality of light paths; and
a multiplexer that combines light from the plurality of light paths to a common light path.
4. A method, comprising:
emitting light from a light source along an input light path;
receiving, by a selector comprising an arrayed waveguide grating, light along the input light path;
outputting, from the selector, light of a first wavelength along a first output of the arrayed waveguide grating;
outputting, from the selector, light of a second wavelength along a second output of the arrayed waveguide grating;
outputting, from the selector, light along a third output of the arrayed waveguide grating;
receiving, at a first detector, the light of the first wavelength
receiving, at a second detector, the light of the second wavelength;
outputting signals from the first detector and the second detector;
determine a ratio between the signals; and
controlling the light source based on the determined ratio to lock a wavelength of the light outputted along the third output to a target wavelength.
5. A system comprising:
a light source that emits light along an input path;
an arrayed waveguide grating configured to:
receive light along the input light path;
output light of a first range of wavelengths along a first output;
output light of a second range of wavelengths along a second output;
output light along a third output;
a first detector that receives the output light of the first range of wavelengths from the first output of the arrayed waveguide grating;
a second detector that receives the output light of the second range of wavelengths from the second output of the arrayed wavequide grating; and
a controller that:
receives signals generated by the first detector and the second detector;
determines a ratio of the signals generated by the first detector and the second detector; and
generate a control signal for the light source based on the determined ratio, wherein the control signal controls the light source to lock a wavelength of light emitted by the light source along the third output of the arrayed waveguide grating to a target wavelength.
6. The system of claim 5 , comprising:
a plurality of light sources that includes the light source that emit light along a plurality of light paths that includes the input path, wherein the arrayed waveguide grating receives light from the plurality of light sources along the plurality of light paths.
7. The system of claim 5 , comprising:
a plurality of light sources that includes the light source that emit light along a plurality of light paths; and
a multiplexer that combines light from the plurality of light paths to a common light path.