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Traceablity Chain for Acoustic Sensors Based on the Direct Definition of the Acoustic Pascal by Optical Method

A new traceability chain for non-standardized acoustic sensors is proposed by using the absolute measurement method of acoustic pressures. The current traceability chain for sound-in-air measurements is based on the laboratory standard microphone. However, this approach has clear limitations and cannot be applied to non-standard sensors such as MEMS microphones. This is because the unit of sound-in-air measurement is indirectly defined via the sensitivity of laboratory standard microphones. As a method to determine the acoustic pressure in an absolute manner, the optical method based on photon correlation is applied and the new traceability chain is proposed based on the direct traceability of the SI unit. As an example, the calibration of a MEMS microphone is demonstrated with the photon correlation method.