kappa L optimization for static and dynamic single longitudinal mode operation in 1.55 mu m lambda /4 shifted DFB LD

kappa L (product of coupling coefficient and cavity length) optimization for static characteristics as well as dynamic behavior in 1.55- mu m lambda /4-shifted distributed-feedback laser diodes (DFB LDs) is presented. Threshold current, differential efficiency and single-longitudinal-mode operation yield are investigated statistically. Dynamic behavior, such as response and wavelength chirping under direct modulation and corresponding transmission performance using DFB LDs are evaluated in connection with kappa L. Transmission experiments which were performed at 2.4 Gb/s with 50- and 80-km 1.3- mu m zero-dispersion fibers are described. It is concluded that a kappa L of 2.3-2.5 is the best value for preparing high-performance lambda /4-shifted DFB LDs suitable for use in high-speed and long-span transmissions.<
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