Investigation of the chirp properties of DFB-EAM’s for high speed baseband and RoF transmission links

Abstract: The ever increasing bandwidth demands driven by an explosion in the mobile device market calls for more and more optical and wireless convergence due to the ability of optical communication systems to transport larger amounts of information to longer distances. Optical modulators are in charge of performing the electrical-to-optical domain conversion, which place them as one of the critical components in optical communication systems. One of the fastest optical modulators is the so called Electro-Absorption Modulator (EAM), which oers very attractive advantages such as the integration with Distributed Feedback (DFB) lasers and its capability of modifying the chirp properties (represented as the parameter) via reverse bias voltage. While a lot of eort has been put in trying to reduce the α parameter as close to 0 as possible, not much work has addressed the performance of integrated Distributed Feedback laser - Electro-Absorption Modulators (DFB-EAMs) handling advanced modulation formats in high speed baseband and Radio over Fiber (RoF) transmission links. This thesis focus on how the chirp aects the transmission of such schemes relevant for optical interconnects and metro-access networks by performing a series of simulations and experiments. The experimental results indicate promising performance including a Bit Error Rate (BER) of 10-4 after 92 km of Standard Single Mode Fiber (SSMF) real time transmission of a 12.5 Gbps On OKeying - Non Return to Zero (OOK-NRZ) signal in real time and no Digital Signal Processing (DSP) and a BER of 10-3 with a 17.4 Gbps four level Pulse Amplitude Modulation (PAM) after 44 km SSMF.