Texas Instruments Incorporated
Integrated microfabricated alkali vapor cell sensor with reduced heading error

Abstract:

An integrated microfabricated alkali vapor cell sensor includes two alkali vapor regions, with a signal path through each. One or two signal emitters, with associated optical signal rotators, such as quarter wave plates, provide circularly polarized input signals into the alkali vapor regions, so that a first signal through the first alkali vapor region is circularly polarized in an opposite direction from a second signal through the second alkali vapor region. Output signals from the two alkali vapor regions are transformed to linearly polarized signals and then measured by one or more signal detectors. A first Larmor frequency is estimated from the output signal from the first alkali vapor region, and a second Larmor frequency is estimated from the output signal from the second alkali vapor region. A heading error-free Larmor frequency is estimated from the first Larmor frequency and the second Larmor frequency.