Tunable millimeter-wave generation with subharmonic injection locking in two-section strongly gain-coupled DFB lasers

Using two-section dual-mode strongly gain-coupled (SGC) distributed feedback (DFB) lasers, tunable millimeter-wave (mm-wave) generation from 18 to 40 GHz can he achieved under CW bias conditions. Due to its high speed and excellent dynamic single-mode yield in SGC DFB lasers, each section can be individually modulated to beyond 10 GHz. Using subharmonic injection locking, the linewidth of the generated mm-wave can be significantly reduced and is found to be less than 30 Hz which is limited by stability of the microwave source and the resolution of the spectrum analyzer. This device provides a useful source to high-bit-rate optical systems and/or high-frequency wireless communications.