Enhancing Single-Mode Stability and Dynamic Characteristics in Complex-Coupled Grating Wire-Like Active-Region Membrane Distributed Reflector Lasers

Complex-coupled (CC) grating wire-like active-region membrane distributed reflector (DR) lasers based on SiO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>/Si substrate were designed for high-speed direct modulation. A time-dependent transfer matrix method, with periodic gain distribution, was used to theoretically analyze these lasers with the spatial-hole-burning (SHB) effect. Better single-lasing mode stability was achieved with anti-phase and in-phase CC-DR lasers than with index-coupled (IC) grating DR lasers with identical index-coupling coefficient and total cavity length. Because of the SHB effect, the side-mode suppression was enhanced in the CC-DR lasers. Further, the modulation characteristics were enhanced. Compared to the IC-DR lasers, 3-dB bandwidth enhancement over 15% was achieved using an anti-phase CC grating with a small index-coupling coefficient under small current injection. In addition, the bandwidth of the in-phase CC-DR lasers with large index coupling was enhanced under high current injection.