Semiconductor Lasers II

Transcription

1 Semiconductor Lasers II Materials and Structures Edited by Eli Kapon Institute of Micro and Optoelectronics Department of Physics Swiss Federal Institute oftechnology, Lausanne OPTICS AND PHOTONICS ACADEMIC PRESS San Diego London Boston New York Sydney Tokyo Toronto

2 Contents Preface xi Chapter 1 Visible-Wavelength Laser Diodes 1.1 Introduction Relevance of visible wavelength lasers Thermal aspects; the temperature-dependence of threshold current Beam properties, astigmatism High-power operation Organization of this Chapter Material systems for visible lasers Introduction The InGaAlP material system The MgZnSSe material system The AlInGaN system The chalcopyrites Epitaxial growth and technology The AlGalnP system The MgZnSSe system Introduction MBE OMVPE Ohmic contacts to p-type ZnSe The AlInGaN system OMVPE/MOMBE Processing and contacting Quantum wells and strain in laser diodes The effects of quantum wells The effects of strain 25 v

3 vi Contents 1.5 InGaAlP laser structures Transverse laser structure with bulk InGaP active layer InGaAlP strained layer quantum well lasers Lateral laser structure: gain-guided lasers Electro-optical properties of gain-guided lasers Lateral laser structure: index-guided lasers Electro-optical properties of index-guided lasers High-power operation Laser diode operation at shorter wavelengths ( nm) Temperature dependence of the threshold current Reliability of InGaAlP lasers Short-wavelength visible lasers (blue-green and blue) II VI injection lasers Introduction The use of CdZnSe strained layer quantum wells and quaternary claddings for blue-green II-VI lasers Reliability of II-IV lasers Gallium nitride-based lasers Conclusions and perspectives toward future developments 62 Acknowledgments 63 References 64 Chapter 2 Long Wavelength (A > 2 /лт) Semiconductor Lasers 2.1 Introduction Wavelength ranges of various laser materials Growth techniques Compounds and alloys of III-V type Brief review of III-V materials for longwavelength laser applications Lasers based on III-V materials Type-II heterojunction InGaSbAs/GaSb InSbAsP/InAs and some other lasers Compounds and alloys of II-VI type Brief review of II-VI materials for longwavelength laser applications 100

4 Contents Vll II-VI-based IR semiconductor laser diodes Compounds and alloys of IV-VI type Brief review of IV-VI materials for longwavelength laser applications IV-VI-based IR semiconductor laser diodes; comments on history Homojunction laser diodes of IV-VI type Heterojunction laser diodes of IV-VI type Quantum-well IV-VI lasers Resume of interband laser properties Threshold and power characteristics Mode control and tunability of the laser emission High-temperature operation Longest wavelength of interband semiconductor lasers Hot-hole (unipolar) semiconductor lasers Unipolar tunneling-based semiconductor lasers Theoretical schemes of the tunneling pumping Characteristics of quantum cascade lasers Nonlinear optical conversion in semiconductors Brief review of applications Conclusions 140 Acknowledgments 142 References 142 Chapter 3 Single-Mode and Tunable Laser Diodes 3.1 Introduction Single-mode laser diodes The Fabry-Perot laser diode The distributed Bragg reflector (DBR) laser Coupled-mode theory for DBR laser Purely passive DBR with nonreflecting end mirror Wavelength selectivity of DBR laser Distributed feedback (DFB) laser diodes Coupled mode theory for DFB laser Spectral linewidth Experimental results 189

5 VUl Contents 3.3 Wavelength tunable laser diodes Physical mechanisms for electronic wavelength tuning in laser diodes Continuously wavelength tunable laser diodes Longitudinally integrated structures Transversely integrated structures Spectral linewidth Physical limitations on tuning range of continuously tunable laser diodes Discontinously tunable laser diodes DBR-type laser structures Wavelength tunable Y-laser Codirectionally mode-coupled lasers Outlook Conclusion 250 References 251 Chapter 4 High-Power Semiconductor Lasers 4.1 Introduction Why high power? Power limitations Case study: index-guided single-mode lasers Beam quality Carrier-induced gain and refractive index The effective index method for finding spatial modes Gain and index waveguiding Filamentation and the a-parameter Brightness, Strehl ratio, and M Brightness Strehl ratio M 2 -factor Case study: monolithic flared amplifier master oscillator power amplifier Thermal management Operating parameters Thermal resistance Characteristic temperature, T Reliability and activation energy 305

6 Contents ix Case study: QUASI-CW 1 cm-wide laser array bars Conclusions 318 Acknowledgments 318 References 318 Chapter 5 Surface-Emitting Lasers Abstract Introduction Configurations of surface-emitting lasers Categorization of surface-emitting lasers Vertical-cavity surface emitting lasers Grating coupled surface emitting lasers Deflecting-mirror surface-emitting lasers Folded cavity semiconductor lasers Basics of vertical cavity surface-emitting lasers Threshold current and quantum efficiency Fundamental elements for vertical cavity surfaceemitting lasers Dielectric multilayer mirrors Semiconductor multi-layer structures Quantum wells for gain medium Periodic and matched gain structures Current and optical confinement Device design and technology Long wavelength surface-emitting lasers GaAlAs/GaAs surface emitting lasers GalnAs/GaAs surface-emitting lasers Short-wavelength surface-emitting lasers Lasing characteristics of VCSELs Ultimate performances Single-mode behavior Polarization characteristics Quantum noise Spontaneous emission control Photon recycling Integrations and applied optical subsystems Photonic-stack integration Surface operating devices and monolithic integrations 358

7 Two-dimensional arrays of surface-emitting lasers Applied subsystems Summary References Index 373