Skip to main content
main-content
Top

About this book

This book demonstrates the implementation of an automated measuring system for very efficient measurement of chromatic dispersion, which uses a modulation phase shift method over long haul of optical single mode fiber. The authors show how a new scheme for measuring chromatic dispersion is adopted in conjunction with a tunable laser (TLS), providing the optical power at required wavelength and digital oscilloscope (DOSC) for measuring the phase difference between microwave signals from transmitter and microwave signals at the receiver. This is a novel approach for real-time chromatic dispersion in optical systems such as optical fibers. The setup used is very simple, accurate and cost effective, compared to other methods such as direct measurement, differential mode delay, polarization mode dispersion measurement and phase delay method.

Table of Contents

Frontmatter

Chapter 1. Concepts and Fundamental Theories of Optical Fibre Dispersions

Abstract
In optical communication, there are different types of distortion that cause the received optical pulse shape to deform in irregular manner. This distortion which is mainly due to dispersion could degrade the phase of light wave signal and reduce the capacity in digital networks. Multimode fibre and single-mode fibre inherently lead to broadening of pulse, which is caused by three basic forms of fibre dispersion, namely, intermodal, chromatic and polarization-mode dispersions, respectively.
Iraj Sadegh Amiri, Masih Ghasemi

Chapter 2. Single-Mode Optical Fibre Dispersions and the Physics Phenomenon Involved

Abstract
This chapter reviews the literature concerning types of dispersion caused by a single-mode optical fibre. As a starting point, Sect. 2.2.1 reviews the single-mode fibre characteristics in one glance. Section 2.2.2 lays out the theory on group-velocity dispersion (GVD). Section 2.2.3 subsequently shows how polarization of light in a waveguide medium leads to dispersion. Section 2.2.4 explains the basics of dispersion on a waveguide. Section 2.2.5 illustrates that a material can also take dispersion into account. Finally, all the information given in this chapter is summarized in Sect. 2.3.
Iraj Sadegh Amiri, Masih Ghasemi

Chapter 3. Study of Optical Fibre Dispersion and Measuring Methods

Abstract
Generally, the design of apparatus configuration plays fundamental and deterministic role over acquired outcome. For any suggested model, there would be many devices available in the laboratory that meet our required expectation on the quantity of proposed variables or parameters. However, some of the devices do not meet the desired reliability, stability or accuracy quality. For the intent of this book, in addition of the above qualities, the response time of measuring device is quite a significant factor. In the following sections, important features and characteristics of active or passive elements will be investigated to exploit them in implementing the design for characterizing dispersion of the optical field.
Iraj Sadegh Amiri, Masih Ghasemi

Chapter 4. Design and Development of Algorithm for Auto-Measurement Voltage and Temporal Parameters of Microwave Signal

Abstract
This chapter presents the main work of this book. An optical device must be programmed to allow auto-measuring and provide high accuracy and reliability of the acquired results. In the following sections algorithms, charts and practical setups for characterizing a low drive voltage modulator and dispersion measurement systems are studied.
Iraj Sadegh Amiri, Masih Ghasemi

Chapter 5. Device Characterizations and Chromatic Dispersion Measurement in Optical Fibres

Abstract
This chapter presents the measurement results obtained from the experiments that have been discussed in the previous chapter. The critical parameters such as wavelength, frequency and DC biasing voltage give different results based on assigned values. External modulator response also limits the dynamic range of these parameters. Since the effect of each parameter on dispersion can be studied separately, in each section of this chapter, each variable parameter will be measured, while the other parameter was made constant. In addition, analysis of multiple critical measurements will be presented to relate the experiment result with the theory.
Iraj Sadegh Amiri, Masih Ghasemi

Chapter 6. Optical Fibre Dispersions and Future Contributions on Electro-optic Modulator System Optimizations

Abstract
In short, this work starts with a brief introduction in Chap. 1 about all general types of dispersion in fibre medium. Estimation and prediction of limitations caused by dispersion are essential considerations in designing any optical system. Hence, in the subsequent chapters, an automated system has been designed for measurement and characterization of dispersion. Chapter 2 discusses about the fundamental theory of dispersion and also the cause factors behind it. Appropriated electrical and optical devices with various functions were assembled for dispersion characterization purpose, and their optimum operating conditions have been studied in Chap. 3. The design of the system and the interlinked communication and control among programmable devices are illustrated in Chap. 4. The employed algorithms for the purpose of controlling, measuring and indexing results are also described in Chap. 4. Final measurement results are discussed practically and theoretically in Chap. 5.
Iraj Sadegh Amiri, Masih Ghasemi

Backmatter

Additional information