For an optical filter consisting of four cascaded optical cavities, two different methods of locking the four cavities to resonance have been investigated. The first being the classical dither...Show moreFor an optical filter consisting of four cascaded optical cavities, two different methods of locking the four cavities to resonance have been investigated. The first being the classical dither locking technique, making use of lock-in amplification to provide PID feedback upon a modulated cavity length. This method has been experimentally implemented using a microcontroller. The second method is a non-linear Q-learning approach based upon dither locking, which has proven capable to lock at least two cavities in simulations. The First method would require the use of polarising beam splitters and waveplates between the cascaded cavities to measure uncoupled reflections, while the second method would require only the total coupled reflection.Show less