Time-resolved chirp measurement of electro-absorption and directly modulated lasers

Abstract

Understanding the effects of chirp on the transmission of signals is of great importance to the system designer. Chirp can have two separate detrimental outcomes in a typical transmission system. The first is that the chirp can interact with the fiber dispersion to create a power penalty, which ultimately limits the number of channels or the distance over which the signal can propagate in today's WDM systems. The second is that chirp can broaden the transmitted spectrum limiting the channel spacing by interfering with adjacent channels even in a short-haul ultra-dense WDM environment. This paper covers time-resolved chirp measurements and the transient and adiabatic chirp properties of electro-absorption and directly modulated lasers. It also discusses methodologies to predict transmission path penalty from time-resolved chirp measurements.