Preface xvii

List of Contributors xix

1 Introduction 1
Kevin Curtis, Lisa Dhar and Liz Murphy

1.1 The Road to Holographic Data Storage 1

1.2 Holographic Data Storage 3

1.2.1 Why Now? 3

1.2.2 Focus of the Book 5

1.2.3 Other Examples of System using the InPhase Architecture 7

1.3 Holographic Data Storage Markets 8

1.3.1 Professional Archival Storage 8

1.3.2 Consumer Applications 11

1.4 Summary 14

Acknowledgements 14

References 14

2 Introduction to Holographic Data Recording 17
William Wilson, Alan Hoskins, Mark Ayres, Adrian Hill and Kevin Curtis

2.1 Introduction 17

2.2 Brief History of Holography 18

2.3 Holographic Basics 19

2.3.1 Introduction 19

2.3.2 Using Holography for Data Storage 22

2.4 Volume Holograms 24

2.4.1 Introduction 24

2.4.2 Kogelnik’s Coupled Wave Equations 25

2.4.3 k-Space Formalism 26

2.5 Multiplexing Techniques 31

2.5.1 Introduction 31

2.5.2 Bragg-Based Techniques 32

2.5.3 Momentum-Based Techniques 34

2.5.4 Correlation-Based Techniques 38

2.5.5 Combinations of Multiplexing Methods 40

2.6 Address Space Limitations on Holographic Densities 41

2.7 Summary 42

References 42

3 Drive Architectures 45
Kevin Curtis, Adrian Hill and Mark Ayres

3.1 Introduction 45

3.2 Collinear/Coaxial Architecture 45

3.2.1 Introduction 45

3.2.2 Coaxial Architecture 46

3.2.3 Collinear Architecture 48

3.3 InPhase Architecture 49

3.3.1 Introduction 49

3.3.2 Angle-Polytopic, Phase Conjugate Architecture (InPhase Architecture) 51

3.4 Monocular Architecture 54

3.4.1 Introduction 54

3.4.2 Monocular Implementation 56

3.4.3 Experimental System 58

3.4.4 Preliminary Experimental Results 59

Acknowledgements 61

References 62

4 Drive Components 65
Kevin Curtis and Brad Sissom

4.1 Introduction 65

4.2 Laser 65

4.2.1 Initial Tapestry Drive Laser Specification 66

4.2.2 Optical System Configuration 67

4.2.3 Electronics 69

4.2.4 Mode Sensor 69

4.2.5 Power Sensor 70

4.2.6 Wavelength Sensor 70

4.2.7 Characteristics of Optical Power and Tuning Range 71

4.2.8 Probability of Single-mode Operation 72

4.2.9 Laser Mode Servo 73

4.2.10 Lifetime of AR Coated Laser Diode 73

4.2.11 Future Developments 73

4.3 SLM 75

4.3.1 Introduction 75

4.3.2 Available SLM Technologies 76

4.3.3 Tapestry Drive SLM Specifications 77

4.3.4 Consumer SLM Specification 78

4.4 Image Sensor 79

4.4.1 Introduction 79

4.4.2 Tapestry Drive CMOS Sensor 80

4.4.3 Image Sensors for Consumer HDS 81

4.5 Beam Scanners 82

4.5.1 Introduction 82

4.5.2 Galvanometer 83

4.5.3 Mechanical Based Scanners 84

4.5.4 MEMs Scanners 85

4.5.5 Liquid Crystal Based Scanners 86

4.5.6 Acousto-Optic Beam Scanner 86

4.6 Isoplanatic Lenses 87

4.6.1 Introduction 87

4.6.2 Characteristics of Isoplanatic Lenses 88

4.6.3 Extremely Isoplanatic Holographic Storage Lens 88

4.6.4 Examples – Symmetric and Asymmetric Phase Conjugation 90

4.6.5 Lens Design Notes: Phase Conjugation and Extreme Isoplanatism 92

4.7 Polytopic Filter 94

4.7.1 Introduction 94

4.7.2 Current Polytopic Filter 95

4.7.3 Mechanical Filtering 96

4.7.4 Interference Filters 97

4.7.5 Thin Film Coating on Curved Surface 98

Acknowledgements 100

References 101

5 Materials for Holography 105
Kevin Curtis, Lisa Dhar and William Wilson

5.1 Introduction 105

5.2 Requirements for Materials for HDS 107

5.2.1 Index Change (M/#) 107

5.2.2 Dimensional Stability 107

5.2.3 Photosensitivity 110

5.2.4 Scatter 110

5.2.5 Absorption Properties 110

5.2.6 Birefringence 111

5.2.7 Optical Quality 111

5.2.8 Manufacturability 111

5.3 Candidate Material Systems 111

5.3.1 Photorefractive Materials 111

5.3.2 Photoaddressable Systems 113

5.3.3 Photochromic Systems 114

5.3.4 Photopolymer Systems 115

5.3.5 Other Materials 116

5.4 Summary 117

References 117

6 Photopolymer Recording Materials 121
Fred Askham and Lisa Dhar

6.1 Introduction to Photopolymers 121

6.1.1 The Holographic Recording Process 121

6.1.2 General Characteristics of Photopolymers 121

6.1.3 Tapestry Two-Chemistry Photopolymer Materials 123

6.2 Photopolymer Design 123

6.2.1 Host Matrix Systems of Photopolymers 123

6.2.2 Photoreactive System of Photopolymers 124

6.3 Holographic Recording in Photopolymers 127

6.3.1 Hologram Formation Through Diffusion in Photopolymers 127

6.3.2 General Use in a HDS System 127

6.4 Rewritable 130

References 132

7 Media Manufacturing 133
David Michaels and Lisa Dhar

7.1 Introduction 133

7.2 Tapestry Media Overview 133

7.2.1 Overview of Disk Structure 133

7.3 Media Manufacturing Process 135

7.3.1 Flow of the Manufacturing Process 135

7.3.2 Molding of Substrates 136

7.3.3 Anti-Reflection Coating 136

7.3.4 Hub and Inner Sealing 136

7.3.5 Bonding 137

7.3.6 Edge and Center Plug Sealing 140

7.3.7 Cartridging 141

7.4 Specifications for the Tapestry Media 142

7.4.1 Substrates 142

7.4.2 Recording Layer 145

7.4.3 Assembled Media 145

7.4.4 Media Performance and Characteristics 148

7.5 Manufacturing of Higher Performance Tapestry Media 148

Acknowledgements 148

References 149

8 Media Testing 151
Kevin Curtis, Lisa Dhar, Alan Hoskins, Mark Ayres and Edeline Fotheringham

8.1 Introduction 151

8.2 Plane Wave Material Testing 151

8.2.1 Introduction 151

8.2.2 Plane Wave Tester Set-up 152

8.2.3 Measurements and Analysis 154

8.2.4 Two Plane Wave Material Testing 157

8.3 Bulk Index Measurements 162

8.4 Scatter Tester 162

8.5 Spectrophotometers/Spectrometers 164

8.6 Scanning Index Microscope 165

8.6.1 Overview 165

8.6.2 System Layout 166

8.6.3 System Response 166

8.6.4 Experimental Example 168

8.7 Interferometers 170

8.8 Research Edge Wedge Tester 172

8.9 Defect Detection 174

8.10 Digital Testing of Media Properties 175

8.10.1 Scatter 175

8.10.2 Media Sensitivities and M/# Usage 176

8.10.3 Media Timing Tests 176

8.10.4 Media Termination Test 176

8.11 Accelerated Lifetime Testing 177

8.11.1 Introduction 177

8.11.2 Media Shelf Life Testing 177

8.11.3 Disk Archive Testing 178

8.11.4 Edge Seal Testing 181

Acknowledgements 182

References 182

9 Tapestry Drive Implementation 185
Kevin Curtis, Ken Anderson, Adrian Hill and Aaron Wegner

9.1 Introduction 185

9.2 Optical Implementation 188

9.2.1 Architecture 188

9.2.2 Field Replaceable Unit (FRU) 190

9.2.3 Shutter 191

9.2.4 Optical Divider 192

9.2.5 Data Path 194

9.2.6 Reference Path 196

9.2.7 Cure System and Toaster 199

9.3 Mechanical Implementation 200

9.3.1 Loader 200

9.3.2 Cooling 200

9.3.3 Integrated Vibration Isolation System and Sway Space 201

9.4 Electronics and Firmware 202

9.4.1 Electronics 202

9.4.2 Firmware 205

9.5 Basic Build Process 209

9.5.1 Overview 209

9.5.2 Drive Alignment for Interchange 212

9.6 Defect Detection 214

9.7 Read and Write Transfer Rate Models 216

9.7.1 Simple Write Transfer Rate Model 217

9.7.2 Simple Read Transfer Rate Model 217

9.8 Summary 219

Acknowledgements 220

References 220

10 Data Channel Modeling 221
Lakshmi Ramamoorthy, V. K. Vijaya Kumar, Alan Hoskins and Kevin Curtis

10.1 Introduction 221

10.2 Physical Model 222

10.2.1 Introduction 222

10.2.2 Details of Model 223

10.2.3 Quality Metrics for the Model 225

10.2.4 Implementation Details and Effects of Parameter Variations 227

10.3 Channel Identification 237

10.3.1 Introduction 237

10.3.2 Comparison of Linear and Nonlinear Channel Identification 239

10.4 Simple Channel Models 241

10.4.1 Amplitude Model 242

Acknowledgements 244

References 245

11 Data Channel 247
Adrian Hill, Mark Ayres, Kevin Curtis and Tod Earhart

11.1 Overview 247

11.2 Data Page Formatting 248

11.2.1 Sync Marks 249

11.2.2 Headers (Bar Codes) 249

11.2.3 Reserved Blocks 250

11.2.4 Border Regions 250

11.2.5 Data Interleaving 250

11.2.6 Modulation 252

11.3 Data Channel Metrics 252

11.3.1 Signal to Noise Ratio 253

11.3.2 Centroid Calculation 254

11.3.3 Intensity Metrics 255

11.3.4 Signal to Scatter Ratio 255

11.4 Oversampled Detection 256

11.4.1 Introduction 256

11.4.2 Resampling Process 257

11.4.3 Alignment Measurement Method 261

11.4.4 Experimental Results 264

11.5 Page Level Error Correction 265

11.5.1 Log Likelihood Ratio 265

11.5.2 Page Level ECC 267

11.6 Fixed-Point Simulation of Data Channel 268

11.7 Logical Format 272

11.7.1 Introduction 272

11.7.2 Terminology 274

Acknowledgements 276

References 277

12 Future Data Channel Research 281
Mark Ayres and Kevin Curtis

12.1 Introduction 281

12.2 Homodyne Detection 281

12.2.1 Introduction 281

12.2.2 Local Oscillator Generation 284

12.2.3 Quadrature Image Pairs 285

12.2.4 Estimating Phase Difference Dw(x,y) 287

12.2.5 Quadrature Image Combination 290

12.2.6 Quadrature Image Resampling 292

12.2.7 Coherent Noise Linearization 293

12.2.8 Simulation Results 294

12.2.9 Phase Sensitivity Issues 296

12.2.10 Local Oscillator and Hologram Alignment 297

12.2.11 Adaptive Homodyne Detection 298

12.3 Phase Quadrature Holographic Multiplexing 300

12.3.1 Phase-Quadrature Recording 300

12.3.2 Phase-Quadrature Recovery 302

12.3.3 Reserved Block Equalization 302

12.3.4 Simulation of Phase-Quadrature Decoding 303

12.3.5 Summary of Improvements 303

12.4 Other Research Directions 304

Acknowledgements 304

References 305

13 Writing Strategies and Disk Formatting 307
Kevin Curtis, Edeline Fotheringham and Paul Smith

13.1 Introduction 307

13.2 Media Consumption 308

13.2.1 Introduction 308

13.2.2 Minimizing the Hologram Size 308

13.2.3 FT Lens Design 309

13.2.4 Phase Mask 311

13.2.5 Short Stacking 314

13.2.6 Skip Sorted Recording Within and Between Tracks 316

13.2.7 Angular Scheduling of Holograms in a Book 318

13.2.8 Angular Fractional Page Interleaving 318

13.3 Scheduling and Write Pre-compensation 320

13.3.1 Introduction 320

13.3.2 Basic Scheduling 320

13.3.3 Pre-cure Calibration 322

13.3.4 Write Pre-compensation Process 325

13.3.5 Thermal Effects on Schedule 327

13.4 Media Formatting 329

13.4.1 Introduction 329

13.4.2 Considerations 329

13.4.3 Format Types with Examples 331

13.4.4 Format Files 335

Acknowledgements 336

References 336

14 Servo and Drive Control 339
Alan Hoskins, Mark Ayres and Kevin Curtis

14.1 Introduction 339

14.2 Holographic System Tolerances 340

14.2.1 Introduction 340

14.2.2 Experimental and Modeled Tolerances 343

14.2.3 Tolerance Summary 350

14.2.4 Tolerance Analysis 351

14.3 Algorithms 353

14.3.1 Introduction 353

14.3.2 Theory of Thermal and Pitch Compensation 354

14.3.3 Dither Align 358

14.3.4 Wobble Servo 360

14.3.5 Other Algorithms 363

14.4 Drive Controls 363

14.4.1 Introduction 363

14.4.2 Record Operation 363

14.4.3 Read Operation 366

14.4.4 Interchange Operation 368

14.4.5 Locating Page 0 369

Acknowledgements 371

References 371

15 Holographic Read Only Memories 373
Ernest Chuang and Kevin Curtis

15.1 Introduction 373

15.2 System Design Considerations 375

15.3 Reader Design 377

15.3.1 Optics and Optomechanics 377

15.3.2 Drive Mechanism 378

15.3.3 Mirror Design and Control 378

15.3.4 Electronics 380

15.3.5 Camera Development 380

15.3.6 Power Consumption 381

15.3.7 Data Channel 381

15.4 Media Design 383

15.5 Two-Step Mastering 385

15.6 Mastering and Replicating Disk Media 390

15.7 Sub-mastering System 392

15.8 Mastering System 393

15.9 Replicating System 394

15.10 Margin Tester System 394

15.11 Experimental Results 395

15.12 Asymmetric Phase Conjugation 396

15.13 Non Fourier Plane Polytopic Filter Designs 397

15.14 Cost Estimates 398

15.15 Product Roadmap 398

15.16 Summary and Future Improvements 399

Acknowledgements 400

References 400

16 Future Developments 403
Kevin Curtis, Lisa Dhar, Liz Murphy and Adrian Hill

16.1 Technology Evolution 403

16.1.1 Archive Drive and Media Evolution 403

16.1.2 Monocular and Holographic Read Only Memory (HROM) Drives 404

16.1.3 Breakthrough Developments 405

16.2 New Applications 405

16.2.1 Archival Storage Market including Near Online Storage 405

16.2.2 Content Addressable Storage 406

16.2.3 Back-Up Application 407

16.2.4 Fixed Disk Applications 407

16.2.5 New Markets 407

16.3 Summary 408

References 408

Index 409