Low-cost optical frequency comb generator based on injected directly modulated distributed feedback semiconductor laser

In this paper, we propose a low-cost optical frequency comb generator based on injected directly modulated distributed feedback semiconductor laser. The comb lines can be tuned by changing injection ratio, detuning frequency and polarization state of the injected signal. The experimentally generated 10 spectral lines have a flatness of 1.5 dB. To generate more spectral lines, three approaches are investigated. By adding phase modulator, 14 spectral lines within 1.8 dB power variation can be achieved.