Digital Modulation Characteristics of Violet InGaN Laser Diodes with Ternary AlGaN and Quaternary AlInGaN Blocking Layers

The outputs of the MQW violet InGaN LD with ternary AlGaN blocking layer (BL) (LD1) and quaternary AlInGaN BL (LD2) have been analyzed and the parameters of LDs have been calculated. Coupling ISE TCAD simulator with MATLAB program has been proposed and utilized to simulate the digital modulation of the LDs. Several operating points on L-I curves of LD1 and LD2 have been selected and examined of pulse response for the purpose of the direct digital modulation investigation. The simulation results indicated that LD2 has relatively lower relaxation oscillation (RO) and higher frequency of RO than LD1. The bit rate, turn-on and turn-off times, and extinction ratio have been investigated and calculated from pulse responses of LD1 and LD2. The maximum bit rate calculated of MQW violet InGaN LDs was 500 Gb/s. In general, it was found that LD2 is better than LD1 for direct digital modulation behavior due to its lower RO, K ratio (photon lifetime/carrier lifetime), damping constant and higher frequency of RO than LD1. Parameters calculated and direct digital modulation results presented in this work are in line with related experimental studies.