Holographic Data Storage E-Book

Kevin Curtis

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 697

Veröffentlichungsjahr: 2011

Beschreibung

Holographic Data Storage: From Theory to Practical Systems is a primer on the design and building of a holographic data storage system covering the physics, Servo, Data Channel, Recording Materials, and optics behind holographic storage, the requirements of a functioning system, and its integration into "real-life" systems. Later chapters highlight recent developments in holographic storage which have enabled readiness for commercial implementation and discuss the general outlook for the technology, including the transition from professional to consumer markets and the possibilities for mass reproduction.

Leseprobe

Copyright

This edition first published 2010

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Library of Congress Cataloging-in-Publication Data

Holographic data storage : from theory to practical systems / Kevin Curtis . . . [et al.].

p. cm.

Includes bibliographical references and index.

ISBN 978-0-470-74962-3 (cloth : alk. paper)

1. Holographic storage devices (Computer science) I. Curtis, Kevin R.

TA1632.H6635 2010

004.5#x2032;65–dc22

2010008437

A catalogue record for this book is available from the British Library.

ISBN: HB: 9780470749623

Contents

Cover

Title Page

Copyright

1. Introduction

1.1 The Road to Holographic Data Storage

1.2 Holographic Data Storage

1.3 Holographic Data Storage Markets

Acknowledgements

References

2. Introduction to Holographic Data Recording

2.1 Introduction

2.2 Brief History of Holography

2.3 Holographic Basics

2.4 Volume Holograms

2.5 Multiplexing Techniques

2.6 Address Space Limitations on Holographic Densities

2.7 Summary

References

3. Drive Architectures

3.1 Introduction

3.2 Collinear/Coaxial Architecture

3.3 InPhase Architecture

3.4 Monocular Architecture

Acknowledgements

References

4. Drive Components

4.1 Introduction

4.2 Laser

4.3 SLM

4.4 Image Sensor

4.5 Beam Scanners

4.6 Isoplanatic Lenses

4.7 Polytopic Filter

Acknowledgements

References

5. Materials for Holography

5.1 Introduction

5.2 Requirements for Materials for HDS

5.3 Candidate Material Systems

5.4 Summary

References

6. Photopolymer Recording Materials

6.1 Introduction to Photopolymers

6.2 Photopolymer Design

6.3 Holographic Recording in Photopolymers

6.4 Rewritable

References

7. Media Manufacturing

7.1 Introduction

7.2 Tapestry Media Overview

7.3 Media Manufacturing Process

7.4 Specifications for the Tapestry Media

7.5 Manufacturing of Higher Performance Tapestry Media

Acknowledgements

References

8. Media Testing

8.1 Introduction

8.2 Plane Wave Material Testing

8.3 Bulk Index Measurements

8.4 Scatter Tester

8.5 Spectrophotometers/Spectrometers

8.6 Scanning Index Microscope

8.7 Interferometers

8.8 Research Edge Wedge Tester

8.9 Defect Detection

8.10 Digital Testing of Media Properties

8.11 Accelerated Lifetime Testing

Acknowledgements

References

9. Tapestry Drive Implementation

9.1 Introduction

9.2 Optical Implementation

9.3 Mechanical Implementation

9.4 Electronics and Firmware

9.5 Basic Build Process

9.6 Defect Detection

9.7 Read and Write Transfer Rate Models

9.8 Summary

Acknowledgements

References

10. Data Channel Modeling

10.1 Introduction

10.2 Physical Model

10.3 Channel Identification

10.4 Simple Channel Models

Acknowledgements

References

11. Data Channel

11.1 Overview

11.2 Data Page Formatting

11.3 Data Channel Metrics

11.4 Oversampled Detection

11.5 Page Level Error Correction

11.6 Fixed-Point Simulation of Data Channel

11.7 Logical Format

Acknowledgements

References

12. Future Data Channel Research

12.1 Introduction

12.2 Homodyne Detection

12.3 Phase Quadrature Holographic Multiplexing

12.4 Other Research Directions

Acknowledgements

References

13. Writing Strategies and Disk Formatting

13.1 Introduction

13.2 Media Consumption

13.3 Scheduling and Write Pre-compensation

13.4 Media Formatting

Acknowledgements

References

14. Servo and Drive Control

14.1 Introduction

14.2 Holographic System Tolerances

14.3 Algorithms

14.4 Drive Control

Acknowledgements

References

15. Holographic Read Only Memories

15.1 Introduction

15.2 System Design Considerations

15.3 Reader Design

15.4 Media Design

15.5 Two-Step Mastering

15.6 Mastering and Replicating Disk Media

15.7 Sub-mastering System

15.8 Mastering System

15.9 Replication System

15.10 Margin Tester System

15.11 Experimental Results

15.12 Asymmetric Phase Conjugation

15.13 Non Fourier Plane Polytopic Filter Designs

15.14 Cost Estimates

15.15 Product Roadmap

15.16 Summary and Future Improvements

References

Acknowledgements

16. Future Developments

16.1 Technology Evolution

16.2 New Applications

16.3 Summary

References

Preface

This book is a result of over 15 years of research and development in holographic data storage, first at AT&T (then Lucent) Bell Laboratories and then at InPhase Technologies. The book's release is timed to roughly coincide with the release of the first ever commercial product using this technology: a professional archive storage drive using removable disk media. While major developments in holographic data storage outside of this effort are described, the focus is on explaining the design, components, and function of the technology used in InPhase's professional drive and two related consumer data storage products.

This book will enable end users of the technology to understand how the drive and media works, and how they are tested. Our hope is that other developers of holographic storage products can use this book as a basic blueprint for developing their own products using this technology.

A wide range of topics from polymer chemistry to error correction codes are covered in this book. The chapters are in large part independent, with a separate list of references at the end of each one. Although each chapter may refer to other chapters for additional detail, there is no assumption that later chapters require a detailed knowledge of earlier ones.

The first five chapters discuss the commercial market for holographic storage, and provide a broad overview of the drive and media technology. Chapters 6–8 discuss the media in greater depth. The technology underpinning the professional drive is considered in detail in Chapters 9–14. Chapter 15 covers read only memories and high speed replication of holographic media; topics that are central to the development of a consumer market for holographic storage. Finally, Chapter 16 concludes with a discussion of the future evolution of the technology and market applications.

A storage product is an amazingly complex device. As a simple example, the firmware controlling the InPhase drive is approximately 1.5 million lines of custom C++ code, which does not include almost another 1.5 million lines of other C and C++ code comprising the drive's operating systems.

The sum total of significant breakthroughs in media, material, control, optics, mechanics, data channel, and testing in the last 15 years is immense. As such, this book represents the work of over 200 people from different companies at various times.

InPhase Technologies was spun out of Bell Laboratories after 6½ years of fundamental research and development. The support of management and wonderful people at Bell Laboratories enabled the start of this long and improbable journey. We sincerely thank these companies and our collaborators, and acknowledge their many contributions to this work.

We have also had significant interaction with, and help from, Hitachi Maxell, Nichia, Alps Electric, Bayer Material Science, Sanyo, Lite-on, IBM, Datarius, and Sony.

This book is dedicated to the employees, investors, and supporters of InPhase Technologies for their amazing contributions and hard work. This book truly is a result of their labor of love. Above all, we acknowledge and thank our families for their patience, understanding, and support over all these years.

Kevin Curtis

Lisa Dhar

William Wilson

Adrian Hill

Mark Ayres

List of Contributors

Ken Anderson, InPhase Technologies, Longmont, CO, USA

Fred Askham, InPhase Technologies, Longmont, CO, USA

Mark R. Ayres, InPhase Technologies, Longmont, CO, USA

Ernest Chuang, InPhase Technologies, Longmont, CO, USA

Kevin Curtis, InPhase Technologies, Longmont, CO, USA

Lisa Dhar, InPhase Technologies, Longmont, CO, USA

Tod Earhart, InPhase Technologies, Longmont, CO, USA

Edeline Fotheringham, InPhase Technologies, Longmont, CO, USA

Adrian J. Hill, InPhase Technologies, Longmont, CO, USA

Alan Hoskins, InPhase Technologies, Longmont, CO, USA

David Michaels, InPhase Technologies, Longmont, CO, USA

Liz Murphy, InPhase Technologies, Longmont, CO, USA

Lakshmi Ramamoorthy, Hitachi Global Storage Technologies Inc., San Francisco, CA, USA

Brad Sissom, InPhase Technologies, Longmont, CO, USA

Paul Smith, InPhase Technologies, Longmont, CO, USA

V. K. Vijaya Kumar, Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA, USA

Aaron Wegner, InPhase Technologies, Longmont, CO, USA

William L. Wilson, InPhase Technologies, Longmont, CO, USA

1

Introduction

Kevin Curtis, Lisa Dhar and Liz Murphy

1.1 The Road to Holographic Data Storage

Digital data are ubiquitous in modern life. The capabilities of current storage technologies are continually being challenged by applications as far ranging as the distribution of content, digital video, interactive multimedia, small personal data storage devices, archiving of valuable digital assets, and downloading over high-speed networks. Current optical data storage technologies, such as the compact disk (CD), digital versatile disk (DVD), and Blu-ray disk (BD), have been widely adopted because of the ability to provide random access to data, the availability of inexpensive removable media, and the ability to rapidly replicate content (video, for example).

Traditional optical storage technologies, including CD, DVD and BD, stream data one bit at a time, and record the data on the surface of the disk-shaped media. In these technologies, the data are read back by detecting changes in the reflectivity of the small marks made on the surface of the media during recording. The traditional path for increasing optical recording density is to record smaller marks, closer together. These improvements in characteristic mark sizes and track spacing have yielded storage densities for CD, DVD, and BD of approximately 0.66, 3.2, and 17 Gb in−2, respectively. BD has decreased the size of the marks to the practical limits of far field recording.

To further increase storage capacities, multi-layer disk recording is possible [1], but signal to noise losses, and reduced media manufacturing yields, make using significantly more than two layers impractical. Considerable drive technology changes, such as homodyne detection and dynamic spherical aberration compensation servo techniques [2–4], have been proposed to deal with the signal to noise losses inherent in multiple layers. However, the use of multiple layers does not address the need for increased transfer rates that are required to effectively use higher disk capacities. In fact, the use of multi-layers makes increasing the transfer rate more difficult. Taking all these issues into consideration, the practical limit for the storage capacity of BD is thought to be around 100 GB, with a transfer rate of 15–20 MB s−1.

Figure 1.1 shows the storage capacity of these optical technologies. The increasing difficulty in continuing to provide higher storage density and data transfer rate has triggered a search for the next generation of optical storage.

Figure 1.1 Optical storage technology roadmap

Alternative optical recording technologies, such as near field [5, 6] and super resolution methods [7, 8], aim to increase density by creating still smaller data marks. As the name suggests, near field methods record in the near field of the lens or aperture, so that the optical diffraction limit does not apply. Super resolution systems typically use special media structures to shorten the recorded marks. However, neither near field nor super resolution methods has shown compelling improvements over BD.

Another approach that produces multiple layers is two-photon recording in homogeneous media [9–11]. This method uses a first laser wavelength to record by producing a local perturbation in the absorption and fluorescence of the media, which introduces a small, localized index change through the Kramers–Kronig relationship [12]. A second wavelength is used to read out the data by stimulating an incoherent fluorescence at a different wavelength. The amount of fluorescence is used to determine whether a one or zero was recorded at a given location. Many layers of bits are recorded to achieve high density. Unfortunately, two-photon approaches suffer from an inherent trade-off between the cross-section of the virtual or real state (sensitivity) and the lifetime of this state (transfer rate). If the sensitivity is high enough for reasonable data density, then the transfer rate is typically low because of the lifetime of the state. In addition, in at least one [9]example , the media is partially erased by each read out. Thus, two-photon techniques face both difficult media development and transfer rate or laser power issues.

With all other optical technologies facing obstacles to significant performance improvements, interest in holographic data storage has dramatically increased in recent years. For example, at the 2008 Joint International Symposium on Optical Memories and Optical Data Storage held in Hawaii, nearly half of the papers were related to holographic systems, media, components, and data channels.

1.2 Holographic Data Storage

Holographic data storage (HDS) breaks through the density limitations of conventional storage technologies by going beyond two-dimensional layered approaches, to write data in three dimensions. Before discussing page-based HDS, which is the focus of this book, we will briefly outline an alternate approach; bitwise holographic storage.