Designs and techniques for actively stabilizing optical cavities in devices such as fiber lasers with reduced power consumption in the active control. The system includes an upstream pressure sensor and a processor programmed to receive signals from the sensor and analyze the signals to determine if secondary fluid flow is proper. The invention significantly reduces the amount of electrical cabling required for communicating with the external controller, and also reduces the required data rate at which information must be supplied from the remote controller to the AEBSC. The trigger event is asynchronous with respect to packets of at least one of the data streams.