Devices, systems, and methods for suppressing optical noise in optically pumped magnetometers

A magnetic field measurement system, comprising:

• a light source configured to emit a light beam;
• an optical fiber configured to transmit the light beam from the light source;
• a variable optical attenuator configured to receive the light beam from the optical fiber and to increase stability of an intensity of the light beam;
• a beam splitter configured to receive the light beam from the variable optical attenuator and divide the light beam into an OPM light beam and a monitor light beam;
• a monitor detector configured to receive and detect the monitor light beam and to generate a monitor signal;
• a vapor cell with alkali metal atoms disposed therein and configured for transmission of the OPM light beam through the vapor cell;
• an OPM detector configured to receive and detect the OPM light beam after transmission through the vapor cell and to generate an OPM signal;
• and
• a group delay filter configured to combine the monitor signal and the OPM signal to generate a reduced noise OPM signal, wherein the group delay filter is configured to account for a phase difference between the monitor signal and the OPM signal when combining the monitor signal and the OPM signal.