Оглавление
Babu Dayal Padullaparthi. VCSEL Industry
Table of Contents
List of Tables
List of Illustrations
Guide
Pages
VCSEL Industry. Communication and Sensing
Dedication
About the Book and Authors Biographies
Foreword
References
Preface
Introduction
Acknowledgments
List of Image Contributions
1 Semiconductor Lasers and VCSEL History
1.1 History and Basics of Semiconductor Lasers
1.1.1 Categorization of Semiconductor Lasers
1.1.2 Light Emission and Absorption in Semiconductors
1.1.3 Birth of Semiconductor Lasers. 1.1.3.1 Homostructure and Double Heterostructure Lasers
1.1.3.2 Quantum Well Lasers
1.1.4 Amplification of Light in Semiconductors
1.1.5 Oscillation Conditions in Semiconductor Lasers. 1.1.5.1 Laser Resonators
<Parameters>
1.1.5.2 Resonant Wavelength
1.1.5.3 Cavity Formation
1.2 Semiconductor Lasers and Manufacturing
1.2.1 Manufacturing Process of Edge‐Emitting Lasers
1.2.2 Vertical‐Cavity Surface‐Emitting Laser
1.3 VCSEL History and Development
1.3.1 Stage I: Initial Concept and Invention. 1.3.1.1 Stage Ia: Invention and Initial Demonstration
1.3.1.2 Stage Ib: First Room‐Temperature Continuous‐Wave Operation
1.3.2 Stage‐II: Spread of Worldwide R&D
1.3.3 Stage III: Extension of Applications and Initial Commercialization
1.3.3.1 LAN for Internet
1.3.3.2 Computer Mouse
1.3.3.3 Laser Printers
1.3.4 Stage IV: Spread of VCSEL Photonics
1.3.5 Stage V: VCSEL Industry
1.4 Timeline and Milestones. 1.4.1 Milestones of VCSEL Research and Development
1.4.2 Single‐Mode and Multi‐Mode Behavior
1.4.3 Major Features of VCSELs
1.4.4 VCSELs as Major Optical Components
1.4.5 VCSELs in Optical Communication and Sensing. 1.4.5.1 The Concept of VCSEL Communication and Sensing
1.4.5.2 VCSELs in Optical Communications
1.4.5.3 VCSELs in Optical Sensing
1.5 State of VCSEL Development. 1.5.1 Published Papers
1.5.2 Toward VCSEL Photonics
1.5.3 Toward VCSEL High‐Volume Manufacturing
1.5.4 Prospects of VCSEL Market
References
2 VCSEL Fundamentals
2.1 Introduction to Lasers
2.2 Basic VCSEL Structure
2.3 Quantum Well Gain Region (Active Region)
2.4 Distributed Bragg Reflector Mirrors
2.5 Light Output Characteristic
2.6 Forward Voltage Characteristic
2.7 Optical Modes
2.8 Beam Divergence
2.9 Modulation Characteristics
2.10 Temperature Characteristics
2.11 Thermal Transient Behavior and Short‐Pulse Operation
2.12 Other VCSEL Structures
2.13 VCSEL Materials
2.14 Summary
References
3 VCSEL Industry: Prospects and Products
3.1 Industry Background
3.1.1 VCSEL Market
3.1.2 VCSEL Chip Demands
3.1.3 VCSEL Attractiveness
3.1.4 VCSEL Die Cost and Foundry Economics
3.2 VCSEL Industry Landscape
3.2.1 The Key “Abilities” of VCSELs
3.2.2 High‐Volume Manufacturing Challenges
3.2.2.1 Epi‐Wafer Growth and F‐P and PL Uniformities
3.2.2.2 Wafer‐Fab (Processing) Specifications
3.2.2.3 Dry Etch Depth Uniformity
3.2.2.4 Wet Thermal Oxidation, Aperture Control and Uniformity
3.2.2.5 Chip Qualification and Reliability Tests
3.2.3 Industry Players
3.2.3.1 Epi‐Houses
3.2.3.2 Process Foundries
3.2.4 Business Models
3.2.5 Supply Chain
3.2.6 Yield Improvements
3.2.7 Cycle Times
3.2.8 COVID‐19 Effects
3.3 VCSEL Commercial Products
3.4 Summary
References
Bibliography
4 Data Communications Applications
4.1 Introduction
4.2 Growing Data
4.3 Data Centers and High‐Performance Computing
4.3.1 Data Centers
4.3.2 High‐Performance Computing
4.3.3 Structure of Data Centers and HPC Centers
4.4 Optical Interconnects. 4.4.1 Introduction
4.4.2 Networking Communications Standards
4.4.3 Optical Transceiver Types
4.4.4 Consumer Connectivity
4.4.5 Techno‐Economic Comparison of Transceiver Technology
4.5 Data Encoding and Multiplexing. 4.5.1 Introduction
4.5.2 Spatial and Wavelength Multiplexing
4.5.3 Pulse‐Amplitude Modulation (PAM‐n)
4.5.4 Discrete Multi‐Tone Modulation (DMT)
4.5.5 Other Modulation Formats
4.5.6 Analog and Radio Access Modulation
4.5.7 Modulation Format Conclusion
4.6 High‐Speed VCSELs
4.6.1 Current Industry Capability
4.6.2 VCSEL Bandwidth Improvement
4.6.3 Photonic Resonance VCSELs
4.6.4 Laser Driver Compensation
4.6.5 Forward Error Correction
4.6.6 Some Record Results
4.7 Optical Link Impairments
4.7.1 Transmitter Impairments
4.7.2 Fiber Impairments
4.7.3 Receiver Impairments
4.8 Energy Efficient VCSELs
4.9 Datacom Market
4.10 Summary
References
5 VCSELs for 3D Sensing and Computer Vision
5.1 Optical Sensors in Consumer Electronics
5.1.1 3D Imaging Technologies
5.1.1.1 Stereo Vision
5.1.1.2 Time‐of‐Flight (TOF)
5.1.1.3 Triangulation Technique and Structured Light
5.1.2 Apple’s 3D Sensing Technology Breakthrough and its Impact
5.2 Why VCSELs for Smart Optical Sensors?
5.2.1 Key Features of High‐Power VCSEL Arrays
5.2.2 Figures of Merit of 2D VCSEL Arrays. 5.2.2.1 Optimizing Losses: Slope Efficiency and Wall Plug Efficiency
5.2.2.2 Fill Factor and Power Scaling
5.2.3 Key Challenges
5.2.3.1 Thermal Dissipation (Heat Sinking) and Packaging
5.2.3.2 Spectral Width, Wavelength Uniformity, and Beam Quality
5.2.3.3 Field‐of‐View (FOV) and Micro‐Optic Illuminators
5.2.3.4 Thermal Limits and Pulse Switching Times
5.3 3D Sensing (Mobile) Products
5.3.1 Smartphones: iOS vs Android
5.3.2 TOF‐Based Proximity Sensors
5.3.3 TOF‐Based Illumination Sensors
5.3.4 Structured‐Light‐Based Face Recognition Sensors
5.3.5 Other Short‐Range 3D Sensors
5.4 Computer Vision and Virtual Reality
5.4.1 Key Aspects of XR (AR, MR, VR)
5.4.2 Augmented Reality (AR)
5.5 3D Sensing Mobile and Camera Industry Prospects (until 2025)
5.6 Summary
References
6 Automotive LiDARs
6.1 Introduction to LiDARs
6.1.1 Classification of LiDARs
6.1.2 Technologies and Sensor Fusion
6.1.3 Advanced Driver Assistance Systems (ADAS)
6.2 Operating Principle of LiDARs. 6.2.1 Time‐Delay and Phase‐Shift‐Based Pulsed Light Detection
6.2.2 Frequency‐Based Continuous Light Detection
6.2.3 Light Transmitters in LiDARs
6.2.4 Light Detectors in LiDARs
6.2.5 Lidar Module with Integrated System‐on‐Chip (SOC)
6.3 VCSELs in LiDAR Industry: Landscape and Direction
6.3.1 Autonomous Shuttles: MaaS/ASaaS
6.3.2 LiDARs in Drones, Robotics, etc
6.4 Key Aspects of LiDARs
6.4.1 Measurement Techniques
6.4.2 Wavelength
6.4.3 Eye Safety
6.4.4 Laser Radiance and Perception
6.4.5 Challenges
6.4.5.1 Background Light Rejection
6.4.5.2 Single Photon Counting Using SPAD Arrays
6.4.5.3 Range Aliasing
6.4.5.4 Power Consumption and System Integration
6.5 Examples of VCSEL‐ and EEL‐Based LiDARs
6.5.1 Solid‐State Flash LiDAR
6.5.2 Solid‐State Addressable‐Flash LiDARs
6.5.3 MEMS Scanning LiDAR
6.5.4 Mechanical Scanning LiDAR
6.5.5 FMCW LiDARs
6.5.6 Optical Phased Array (OPA) and Si‐Photonics‐Based LiDARs
6.5.7 VCSELs for in‐Cabin Sensing
6.6 Automotive Communication: IVE (Infotainment) and C‐V2X
6.7 Market Summary
References
7 Illumination, Night Vision, and Industrial Heating
7.1 Introduction
7.2 Optical Properties of Illumination Sources
7.3 Commercial Examples of VCSEL Illuminators
7.4 VCSEL‐Based Industrial Heating
7.5 Summary
References
8 Single‐Mode VCSELs for Sensing Applications
8.1 Introduction
8.2 Single‐Mode VCSELs
8.2.1 Spatial Mode Control
8.2.2 Polarization Control
8.2.3 Wavelength Tuning Principles
8.3 Single‐Mode VCSEL Application Examples
8.3.1 Laser Mouse and Finger Navigation
8.3.2 Optical Encoders
8.3.3 Laser Printers
8.3.4 Gas Sensors
8.3.5 Atomic Clocks and Magnetometers
8.3.6 Optical Coherence Tomography
8.3.7 Other Emerging Applications
8.4 Summary
References
9 Single‐Mode VCSELs for Communications Applications
9.1 Introduction
9.2 LW‐VCSEL Design and Manufacturing
9.2.1 LW‐VCSEL Structures
9.2.2 1310 nm VCSEL
9.2.3 VCSELs in the 1550 nm Band
9.2.4 Other Wavelengths for Data Communications
9.3 Quantum Communications
9.4 Summary
References
10 Future Prospects
10.1 VCSEL Industry
10.2 Datacom VCSELs
10.3 VCSEL Arrays for 3D Sensing (Short Distance)
10.4 VCSEL Arrays for 3D Sensing and Imaging (Long Distance)
10.5 kW‐Level VCSEL Arrays for Industrial and Night Vision
10.6 Single‐Mode VCSELs for Communication and Sensing
10.7 Quantum Technologies
10.8 Neuromorphic/Neurophotonic Technologies
10.9 Biomedical/Bio‐Photonic Applications
10.10 New Directions of VCSEL Technologies (as of March 2021)
10.11 Concluding Remarks
References
Appendix A VCSELs Design Engineering
A.1 Background
A.1.1 Key Stages of VCSEL Mass Production
A.1.2 Basic Design Elements
A.1.2.1 Active Region (Optical Cavity)
A.1.2.2 Distributed Bragg Reflectors (DBRs) and GRIN Layers
A.1.2.3 Oxide Window and Current Confinement
A.1.2.4 Heat Management and Thermal Limitations
A.1.3 Device Modeling and Commercial Software
A.1.4 High‐Performance Designs for Communication and Sensing
A.1.4.1 High‐Speed Designs for 850 nm Datacom
A.1.4.1.1 Differential Gain (dg/dN)
A.1.4.1.2 Optical Confinement Factor (Γ )
A.1.4.1.3 Photon Lifetime (τp)
A.1.4.1.4 Electrical Parasitics (Cm and Rm)
A.1.4.1.5 Narrow Linewidth and Low Noise Designs
A.1.4.1.6 Junction Temperature
A.1.4.2 High‐Power 940 nm VCSEL Design
A.1.5 Summary
References
Appendix B Epitaxial Growth Engineering
B.1 Technologies and Materials for VCSELs
B.1.1 Existing Technologies
B.1.2 Selection of Materials
B.1.3 Market Drivers
B.2 Epitaxial Growth
B.2.1 Growth Techniques: MBE and MOCVD
B.2.2 Key Reactor Parameters
B.2.2.1 Growth Temperature
B.2.2.2 V‐III Ratio
B.2.2.3 Growth Rate
B.2.2.4 Background Dopant Levels
B.3 Reactor Readiness and Calibrations
B.3.1 Theoretical Estimations and Calibration Flow
B.3.1.1 Al(x) Mole Fraction and Doping Concentration
B.3.1.2 p‐ and n‐ Mirror Reflectivity
B.3.1.3 QW Photoluminescence
B.3.1.4 Epitaxy Substrates
B.3.1.5 Precise Dopant Source Analysis
B.3.2 Mini and Full VCSEL Structure Growth
B.4 Post‐Growth Characterizations and Acceptance
B.5 Epitaxial Growth on Large‐Sized Wafers
B.6 Summary
References
Bibliography
Appendix C Wafer Process Engineering
C.1 Background of Wafer Processing
C.1.1 Process Configurations
C.1.2 Photomask Design
C.2 Wafer Processing Methods: DOE and Lot
C.2.1 Front‐End Processing
C.2.1.1 Metallization
C.2.1.2 Mesa Etching
C.2.1.3 Passivation
C.2.1.4 Wet Thermal Oxidation
C.2.2 Back‐End Processing
C.2.2.1 Back Side Contact and Thinning
C.2.2.2 Dicing
C.2.2.3 Visual (Final) Inspection
C.2.2.4 ESD Issues
C.2.2.5 WTS and WPT
C.2.3 Generic Process Flows
C.2.3.1 High‐Speed VCSEL Flow
C.2.3.2 High‐Power VCSEL Array Flow
C.2.4 Wafer Process: Summary and Conditions
C.2.5 Quality Gates: Critical Points and Data Handling
C.3 Wafer Probe Measurements
References
Bibliography
Appendix D Wafer Level Testing
D.1 Introduction
D.2 Post‐Epitaxial Characterization
D.3 Wafer Fabrication Data
D.4 Wafer Level Performance Test
D.5 Package Level Validation
D.6 Summary
References
Appendix E Reliability and Product Qualification
E.1 Introduction
E.2 Reliability Model Development
E.3 Failure Modes in VCSELs
E.3.1 Electrical Overstress (EOS)
E.3.2 Electrostatic Discharge (ESD)–Induced Damage
E.3.3 Humidity‐Accelerated Failures
E.3.4 Radiation Tolerance
E.3.5 Long‐Term Wear‐Out Failures
E.3.6 Difference between GaAs and InGaAs
E.4 Array Reliability and Sparing
E.5 Considerations for High‐Power 2D VCSEL Arrays
E.6 Qualification Standards
E.7 Ongoing Quality Verification
E.8 Summary
References
Appendix F Eye Safety Considerations
References
Appendix G Laser Displays and TV
G.1 What is a Laser Display?
G.1.1 Laser Display Format
G.1.2 Laser Projector Principle
G.2 Displays and Color Gamut
G.3 Laser Light Sources for Display. G.3.1 Displays and Lasers
G.3.2 RGB Light Sources
G.3.3 Laser Projector Components
G.3.4 Laser Projector and its Applications
G.4 Laser Backlight Method
G.5 Summary of Laser Displays
References
Note
Appendix H Red VCSELs
H.1 Introduction
H.2 Data Communications
H.3 Blood Oximetry
H.4 Hair Regrowth
References
Appendix I GaN‐Based VCSELs
I.1 AlGaInN Laser Materials
I.2 AlGaInN Laser Development
I.3 AlGaInN Blue VCSELs
I.4 AlGaInN Green VCSELs
I.5 White Light Generation by VCSELs
References
Appendix J Photodetectors
J.1 Introduction. J.1.1 Classification of Photodetectors
J.1.2 Photodetectors Materials and Operation Principles
J.2 Noise in Photodetectors
J.3 Photodetectors for Communication and Sensing
J.3.1 p‐n and p‐i‐n PDs
J.3.2 Avalanche Photodiode (APD)
J.3.3 Single‐Photon APD (SPAD)
J.3.4 Silicon Photomultiplier (Si‐PM)
J.3.5 Dynamic Photodiode (DPD)
J.3.6 PDs Integrated with Image Sensors
J.3.7 CMOS‐Based SPAD Arrays
J.4 Summary of Photodetectors
References
Image Gallery
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