Comparison of harmonic and intermodulation distortions of directly modulated interband lasers and quantum cascade lasers

In this paper, a comparison of second harmonic and two-carrier intermodulation distortion of three near infrared interband lasers and three mid-infrared quantum cascade lasers is reported. These distortions arise from direct intensity modulation of semiconductor lasers. To make the comparison, the distortions in dBs are plotted against the frequency of the RF subcarrier. The lasers are considered to have the same DC optical power output and optical modulation depth