Spectral linewidth reduction (580 kHz) in structure-optimised 1.5 mu m butt-jointed distributed Bragg reflector lasers

Spectral linewidth reduction due to structural optimisation is studied in butt-jointed DBR lasers. It is theoretically shown that a laser structure with passive DBR regions on both sides of an active region is effective in reducing the linewidth. Based on theoretical calculation, 1.5 μm butt-jointed DBR lasers are fabricated entirely by MOVPE growth. Linewidth is reduced to 580kHz in structure-optimised 1.5 μm buttjointed DBR lasers.