Noise rejection for optomechanical devices

A method for tracking a mechanical resonance of a proof mass assembly, the method comprising:

• generating, by a circuit, an optical signal comprising a central carrier corresponding to an optical resonance of the proof mass assembly using a tuning signal;
• modulating, by the circuit, the optical signal at a frequency corresponding to one quarter of a Full Width at Half Maximum (FWHM) of the optical resonance of the proof mass assembly to generate a partially modulated optical signal comprising the central carrier, a first optical frequency component corresponding to the optical resonance plus one quarter of the FWHM of the optical resonance, and a second optical frequency component corresponding to the optical resonance minus one quarter of the FWHM of the optical resonance;
• filtering, by the circuit, the partially modulated optical signal to remove the central carrier from the partially modulated optical signal to generate a filtered optical signal;
• modulating, by the circuit, the filtered optical signal to generate a modulated optical signal driven to the mechanical resonance of the proof mass assembly;
• and
• generating, by the circuit, the tuning signal using a difference between a Direct Current (DC) intensity level of the first optical frequency component in the modulated optical signal and a DC intensity level of the second optical frequency component in the modulated optical signal.

An optomechanical system for tracking a mechanical resonance of a proof mass assembly, the optomechanical system comprising:

• a circuit configured to:
• generate an optical signal comprising a central carrier corresponding to an optical resonance of the proof mass assembly using a tuning signal;
• modulate the optical signal at a frequency corresponding to one quarter of a Full Width at Half Maximum (FWHM) of the optical resonance of the proof mass assembly to generate a partially modulated optical signal comprising the central carrier, a first optical frequency component corresponding to the optical resonance plus one quarter of the FWHM of the optical resonance, and a second optical frequency component corresponding to the optical resonance minus one quarter of the FWHM of the optical resonance;
• filter the partially modulated optical signal to remove the central carrier from the partially modulated optical signal to generate a filtered optical signal;
• modulate the filtered optical signal to generate a modulated optical signal driven to the mechanical resonance of the proof mass assembly;
• and
• generate the tuning signal using a difference between a Direct Current (DC) intensity level of the first optical frequency component in the modulated optical signal and a DC intensity level of the second optical frequency component in the modulated optical signal.