**Meet the editor**

Sisir Kumar Garai was born in 1971 in West Bengal, India. He received his M.Sc. degree in Physics in 1994 and M.Tech. degree in Microwaves in 1998 and was awarded his Ph.D. degree in Science (Physics) in 2012 from The University of Burdwan, West Bengal, India. His fields of research interest include optoelectronics, optical computation and communication, and he has contribut-

ed more than forty papers in various national and international journals and edited a book entitled *Selected Topics on Optical Amplifiers in Present Scenario* (ISBN 978-953-51-0391-2; InTech; March 3, 2012). He received the best paper presentation award in the 16th West Bengal State Science and Technology Congress (2009), and his name is also included in Marquis Who's Who (2010 and 2011) and by the International Biographical Centre (IBC), Cambridge, 2011. Dr. Garai is the author of the book *Fundamentals of Frequency Encoded Optical Logic Processors* (LAP Lambert Academic Publishing, Germany, 2015). He has been an Assistant Professor in the Department of Physics at the M.U.C. Women's College, Burdwan, West Bengal, India, since 2002.

## Contents

#### **Preface XI**



#### Chapter 7 **Optimized Design of Yb3+/Er3+-Codoped Phosphate Microring Resonator Amplifiers 149** Juan A. Vallés and R. Gălătuş

## Preface

Chapter 7 **Optimized Design of Yb3+/Er3+-Codoped Phosphate Microring**

**Resonator Amplifiers 149** Juan A. Vallés and R. Gălătuş

**VI** Contents

To provide Internet-based communication network, the speed of computing as well as of data processing should be high enough with a transmission medium of enormous potential bandwidth having the capability to handle vast amount of information. On the other hand, conventional electronic technology has already reached its ultimate speed limit (40 Gb/s) through the limitation of miniaturization of chips and bandwidth limitation, and obviously it creates data traffic jam in Internet-based networking services. Therefore, a drastic solution to this acute problem is needed, and scientists and technologists promote their thinking to a totally different track from the conventional electronic system so that we can further im‐ prove on the computer performance and data signal processing with a potential communi‐ cating medium to such an extent that we will be well prepared to accept the present and future challenges of data traffic.

Optical computing and optical signal processing are strongly believed to be the most feasi‐ ble technology that can provide the way out of the extreme limitations imposed on the speed and the complexity of present-day computation and communication by conventional electronics. Optics provides higher bandwidth than electronics, which enables more infor‐ mation to be carried simultaneously and data to be processed in parallel with impressive increase in speed by several orders of magnitude over that of the electronic signals. If the parallelism of optics were associated with fast switching speed of optical devices, it would result in surprising computational speed and processing of data.

Considering the present scenario of speed and bandwidth limitations of electronic comput‐ ing, signal processing and the future problem of data traffic, scientists, technologists and researchers are working in the field of all-optical data and signal processing. The role of the optical amplifier is indispensable in such optical communication network. Over the past two decades, optical amplifiers such as erbium-doped fibre amplifier (EDFA), Raman amplifier and semiconductor optical amplifier (SOA) are the prime optical network functional compo‐ nents and have many functional applications, such as wavelength conversion, regeneration, wavelength selection, booster, in-line amplification, in-node optical preamplification and mid-span spectral inversion.

The topics selected in this book cover some advanced functionalities of SOAs in the field of optical communication network. This book also includes the role of broadband S-band to Lband EDFA in WDM communication network, and it also covers the optimized design tech‐ nique of Yb3+/Er3+-codoped phosphate microring resonator amplifiers.

The book contains seven chapters. The first chapter deals with an efficient and validated time-domain numerical modelling of SOAs and SOA-based circuits; the second chapter is based on the working of gallium nitride-based SOAs. The role of SOAs for the next genera‐

tion of high-data-rate optical packet-switched network is presented in Chapter 3. Chapter 4 deals with the all-optical semiconductor optical amplifier based on quantum dots (QD-SOA) and its function as an arithmetic processor. In Chapter 5, the authors have presented the role of SOAs in intensity modulation of the optical pulses and their use in deterministic timing jitter and peak pulse power equalization analysis. In Chapter 6, the investigation of broad‐ band S-band to L-band EDFA module is presented, and Chapter 7 includes the optimized design technique of Yb3+/Er3+-codoped phosphate microring resonator amplifiers.

All the topics selected for this book are very interesting and well organized, and the presen‐ tation is also very lucid. This book covers the emerging applications of optical amplifiers in the present scenario, and I believe that the book will be of great value to the researchers in the field of optical communication, component suppliers, postgraduate students, academics and anyone seeking to understand the trends of optical amplifiers in the present scenario and the consequent changes in optical amplifier design and technology.

Without the unstinting support from so many persons, it would not have been possible for me to edit this book. Therefore, I feel compelled to express my gratitude to all of them. First of all, I would like to express my indebtedness to all the writers of this book for contributing their valuable research works. Their patience and insights from which I have learnt will surely benefit me for the rest of my life. I am very grateful to Ms. Iva Simcic, Publishing Process Manager, for her incessant support in numerous ways to enable me to do the edito‐ rial work. I wish to convey my thanks to the technical editorial staff and all other staff mem‐ bers of the publisher. I am grateful to my family as well for their constant encouragement and support. Finally, I would like to extend my sincere thanks to all my colleagues at M.U.C. Women's College, Burdwan, for their incessant encouragement.

We shall deem our effort amply rewarded if the book wins the appreciation of the users.

**Dr. Sisir Kumar Garai** Assistant Professor of Physics M.U.C. Women's College, Burdwan West Bengal, India
