This PFC main goal is to introduce new approaches on the chromatic dispersion measurementfield, based on the big range of possibilities the setup of a general standard RF-tonemodulation chromatic modulation method provides, and to show its good performancepointing towards a real-time on-line monitoring system for optical communication networks.The project’s objectives are defined considering two well-delimited stages.First, we will study some standard RF-tone-addition techniques for measuring chromaticdispersion, specifically the Modulation Phase Shift Method (MPSM) [2] and the Peucheret`sMethod [3]. We will analyze their operating principles, recognize all the variables involved intheir basic configurations and evaluate their performances under different measurementconditions.We will also study the implications of real-time on-line monitoring of chromatic dispersion inoptical networks. We have to consider that the test signal has to travel together with the data;therefore, it is a priority to keep the optical carrier unaltered in the transmission and receptionprocedures.This background will help us to identify the main drawbacks of both methods which motivatethe proposal of a new improved technique based on a similar mathematical basis but withbetter performance in terms of accuracy and cost trade-off.The general features of this new approach will be exposed on a basic setup designed for alaboratory environment, so that we can contrast it with the conventional techniques. Thismethod dubbed Asymmetric Modulation Bias-Controlled Method (ABCM) will focus on RF modulated signal amplitude and will take advantage of its direct relation with chromaticdispersion.One of the basic building blocks of these standard methods is the device that imposes the RFpure-tone modulation to the optical signal, namely the Mach-Zehnder interferometricmodulator usually in the conventional push-pull configuration and biased at the quadraturepoint. In the context of the new improved CD measurement methods, we will observe how theMach-Zehnder modulator Bias Voltage concept gains relevance; becoming the main variable tobe handled by the use of a dual drive Mach-Zehnder modulator in asymmetric configuration.Finally, we will analyze this ABCM method performance while some fixed parameters (RFFrequency, Nominal Dispersion, resolution) take different values in order to find out theoptimum operating conditions.The problem when trying to apply the ABCM to the real-time on-line monitoring of opticalnetworks is that it relies in the eventual cancellation of the optical carrier which in a networkmonitoring application is shared with the data and it is essential for a proper data recovery.We must find an alternative where this optical carrier cancellation is not essential for themonitoring function and that would be the ABCM-SC (SC for suppressed carrier)Therefore, on a second stage, we will focus on giving this new perspective about dispersionmeasurement a direct application in optical communications field. We will restructure theABCM into a practical dispersion monitoring system for optical communication networks. Thisimproved monitoring technique will be based on a proof-of-concept study (no real datatransmission considered) to evaluate the method’s performance in terms of accuracy,robustness and adaptability, building the basis for data transmission experiments in futureprojects.An important aspect to take into account will be the way we carry out the RF tone additionprocedure without altering the optical carrier (transmitted data). To accomplish thisrequirement we will use a Bessel function analysis to achieve a carrier-suppressed modulationof the RF tone, which introduces another important handling parameter: the RF ToneAmplitude.We will also be concerned about isolating the emitter part (where data is transmitted) fromthe monitoring point (where dispersion is measured), but at the same time complementingeach other to operate in a real-time situation.Finally, we will study the requirement of including the second RF harmonic detection togetherwith the first harmonic as it adjusts better to a real-time monitoring system and increases theaccuracy level in chromatic dispersion measurement.