Importance of rapid damping of relaxation oscillations for high-performance optical communication systems

The performance of a 1.55 ¿m lightwave transmission system employing directly modulated single-frequency semiconductor lasers depends on the dynamic characteristics such as the wavelength chirp and the damping of relaxation oscillations. Numerical simulations which include the effect of fibre dispersion and decision-time jitter on the detected power show that rapid damping of relaxation oscillations is critically important for high-bit-rate systems. We discuss how the system performance can be improved by optimising certain laser parameters.