Stability of master-slave laser system with nonperfect isolator

Injection locking and the stability of two lasers including an unintentional coupling from a slave to a master laser and a weak-optical feedback from a passive-external cavity to the master laser are discussed. The dynamic behavior for various coupling conditions was solved by studying the small fluctuations around the stationary state. When the coupling from the master to the slave laser is taken into account, the slave laser is stable near the boundary of the locked state, with its natural frequency larger than that of the injected light. An unstable slave laser becomes stable with an increasing injection level if it operates at threshold. At threshold, the unintentional coupling does not change the stable region of a weak injection. The region of strong injection is more sensitive to this coupling.<
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