Selective-area MOCVD growth for novel 1.3 /spl mu/m DFB laser diodes with graded grating

We demonstrate a new approach to realize the graded grating, which is effective to improve the modulation characteristics of DFB laser diodes (LDs) for analog optical transmission, by using selective-area-growth (SAG) technique. Ideal parabolic thickness profile and the thickness enhancement ratio as high as 4.6 in the grating layer have been realized by optimizing the mask shape using the simulation technique for SAG. We have also successfully realized the high light-current linearity in 1.3 /spl mu/m DFB-LDs with graded grating for the first time. It has been shown that the LDs have excellent distortion characteristics.