WAVELENGTH-TUNABLE ASYMMETRIC CLADDING RIDGE-WAVE-GUIDE DISTRIBUTED-BRAGG-REFLECTOR LASERS WITH VERY NARROW-LINEWIDTH

Narrow-linewidth ridge-waveguide distributed Bragg reflector (DBR) las ers with asymmetric cladding are demonstrated. This design requires on ly a single epitaxial growth of an asymmetric cladding laser structure while the grating and the ridge waveguide are fabricated after the gr owth. These lasers have a threshold current as low as 9 mA, a slope ef ficiency of 0.3 W/A, and a T-0 of 100 K. Wavelength tuning of 8 mn is achieved by current injection heating of the DBR section. A spectral-l inewidth minimum of 36 kHz is achieved at an output power of 20 mW and is limited by linewidth rebroadening due to current injection in both the gain section and DBR section.