Smart Phase Locking of the Frequency of Two Identical Lasers to Each Other

The paper considers the main aspects of ensuring phase-locked looping of two lasers to each other. This problem is extremely important for laser physics. In traditional systems, this binding was carried out by using two circuits, namely frequency tuning and phase tuning. The tuning loop provides capture conditions, but in capture mode, it interferes with the operation of the phase loop and reduces the accuracy of the entire system. In addition, this solution is unnecessarily cumbersome, which increases the cost of the system and complicates its implementation, configuration and use. The proposed technical solution is based on the use of other types of phase detectors, namely, frequency-phase detectors. To be able to use them, a pulse shaper must be introduced into the system, which converts the input harmonic signals containing amplitude modulation and high frequency noises, and probably, low-frequency noise, to standard fixed-level signals with sharp edges. In this case, the propagation of fronts due to the remnants of high-frequency noise is strictly unacceptable, which requires the use of a Schmitt trigger, and for its effectiveness requires a relatively constant amplitude of the input signal. If this is not the case, an automatic level stabilization system is required. All these changes in the aggregate are still simpler than using two auto tuning circuits. In addition, it provides great ease of implementation, customization and use. Basic circuit diagrams of the main nodes are presented, as well as the relationships and method for adjusting the regulator in order to ensure high accuracy of the phase-locked loop.