Novel modulated-master injection-locked 1.55-μm VCSELS

We report a novel optical injection-locking configuration using a directly-modulated master VCSEL to injection-lock a slave VCSEL. We demonstrate an interesting RF modulation response for the modulated master laser. An RF gain up to 30 dB is attained for frequencies greater than a certain critical frequency f_c which is ∼10 GHz here and increases with the injection power. In addition, an RF phase change of 2π is achieved above f_c by varying the wavelength detuning. The slope of the phase-frequency curve represents an equivalent slow or fast light attained through the slave laser. We incorporate an amplifier model to explain this novel modulated-master injection-locked VCSEL configuration. Simulations show good qualitative agreement with the experimental results.