How the coherent output of a laser can be built from the spontaneous emission noises is discussed in terms of quantum mechanics and compared briefly with its semiclassical treatment. The current explanation of passive mode locking by Kryukhov and Letokhov is discussed and a new deterministic description by Haus and Ausschnitt is discussed and compared with the K-L model. Some problems are found in their assumptions. Our Korad K-l ruby laser and its related detection systems are described. The fabrication and specifications of some components are described and examined, and some important para meters, such as threshold inversion, is evaluated.