Injection locking of a semiconductor laser to a multi-frequency reference beam

Injection locking is a well known and commonly used method for coherent light amplification. Usually injection locking is done with a single-frequency seeding beam. In this work we show that injection locking may also be achieved in the case of multi-frequency seeding beam when slave laser provides sufficient frequency filtering. One relevant parameter turns out to be the frequency detuning between the free running slave laser and each injected frequency component. Stable selective locking to a set of three components separated of $1.2,$GHz is obtained for (positive) detuning values between zero and $1.5,$GHz depending on seeding power (ranging from 10 to 150 microwatt). This result suggests that, using distinct slave lasers for each line, a set of mutually coherent narrow-linewidth high-power radiation modes can be obtained.