Verification of an in situ calibrated optomechanical accelerometer for use as a strong ground motion seismic reference

Optomechanical accelerometers offer in situ traceability to the International System of Units (SI) through laser interferometry, providing an alternative to a calibration chain using instrumented shakers. Here, we examine the "self-calibrating" property of a prototype optomechanical accelerometer for use as a seismic reference. We report the optomechanically derived sensitivity of the accelerometer and compare its self-calibrated output to input accelerations from an instrumented shaker, finding agreement to be within ±1 %. The comparison spanned frequencies between 3 Hz and 30 Hz, and for sinusoidal accelerations with amplitudes ranging from 0.01 m/s2 to 0.6 m/s2. These results are evidence that optomechanically derived sensitivity calibration can be equivalent to established international methods for primary calibration.