A gas species monitoring system includes a laser, a fiber amplifier configured to receive an input signal from the laser and generate an amplified signal, and a variable optical attenuation system configured to receive at least a portion of the amplified signal and generate an attenuated signal for delivery to a measurement point, where the measurement point includes a gaseous fluid. The system further includes a detector configured to receive and process a signal from the measurement point so as to obtain a measured signal that correlates with the presence of a gas species within the gaseous fluid at the measurement point, and a processor in communication with at least the variable optical attenuation system and the detector. The processor controls the variable optical attenuation system based upon the measured signal.