Structural dependence of three-phase-shift distributed feedback semiconductor laser diodes at threshold using the transfer matrix method

The three-phase-shift (3PS) distributed feedback (DFB) laser is known to have improved performance over the lambda /2 DFB laser because the spatial hole burning effect is suppressed. When optimizing the structural design of the SPS DFB laser, the threshold gain difference and the field distribution along the laser cavity have been selected as the design criteria. Using the transfer matrix method, it is found that the optimum phase-shift values and their positions are in trade-off when one attempts to optimize both the gain difference and field uniformity simultaneously.