Opto-Electronics Research Laboratories *Compound Semiconductor Device Division NEC Corporation, 4-1 -1 Miyazaki, Miyamae-ku, Kawasaki 213. Japan

KL optimization for static characteristics as well as dynamic behavior in 1.55 pm 1/4 shifted DFB LDs are presented. Threshold current, differential efficiency and singlelongitudinal-mode operation yield were investigated statistically. Dynamic behavior such as response and wavelength chirping under direct modulation, and corresponding transmission performance using DFB LDs, were evaluated in connection with K L. Transmission experiments were demonstrated at 2.4 Gb/s with 50 and 80 km 1.3 pm zero-dispersion fibers. These results enable us to design high performance DFB LDs suitable for high-speed and long-span transmissions.