Guided-Wave Optoelectronics. Questo articolo non è disponibile.Guided-Wave Optoelectronics

The first guided-wave components that employed signals in the form of light beams traveling along thin films were fabricated a little more than two decades ago. The parallel development of semiconductor lasers and the subsequent availability of low-loss optical fibers made possible the imple­ mentation of completely optical systems for communications, signal pro­ cessing and other applications that had used only electronic circuitry in the past. Referred to as integrated optics, this technology has been rein­ forced by utilizing electronic components that act as controlling elements or perform other functions for which the optical counterparts are not as effec­ tive. The broader area thus generated was aptly named optoelectronics and it currently represents a fascinating, rapidly evolving and most promising technology. Specifically, the amalgamation of electronic and optics compo­ nents into an integrated optoelectronics format is expected to provide a wide range of systems having miniaturized, high speed, broad band and reliable components for telecommunications, data processing, optical computing and other applications in the near and far future. This book is intended to cover primarily the optical portion of the op­ toelectronics area by focusing on the theory and applications of components that use guided optical waves. Hence all aspects of integrated optics are dis­ cussed, but optoelectronic components having primarily electronic rather than optical functions have not been included. Each chapter has been writ­ ten by experts who have actively participated in developing the specific areas addressed by them.

1. Introduction.- 1.1 Overview.- 1.2 Organization of the Book.- References.- 2. Theory of Optical Waveguides.- 2.1 Ray Optics of the Slab Waveguide.- 2.1.1 Refraction and Reflection.- 2.1.2 Guided Modes.- 2.1.3 The Goos-Hänchen Shift.- 2.1.4 Effective Guide Thickness.- 2.2 Fundamentals of the Electromagnetic Theory of Dielectric Waveguides.- 2.2.1 Maxwell’s Equations.- 2.2.2 Modes of the Waveguide.- 2.2.3 The Wave Equations for Planar Guides.- 2.2.4 Mode Properties Following from Symmetry.- 2.2.5 Orthogonality of the Modes.- 2.2.6 Mode Expansion and Normalization.- 2.2.7 The Variation Theorem for Dielectric Waveguides.- 2.2.8 Power Flow and Stored Energy in a Dielectric Waveguide.- 2.2.9 Variational Properties of the Propagation Constant.- 2.3 Modes of the Planar Slab Guide.- 2.3.1 TE Modes.- 2.3.2 TM Modes.- 2.3.3 Multilayer Slab Guides.- 2.4 Planar Guides with Graded-Index Profiles.- 2.4.1 The Parabolic Profile (Harmonic Oscillator).- 2.4.2 The “1/cosh2” Profile.- 2.4.3 The Exponential Profile.- 2.4.4 Index Profiles with Strong Asymmetry.- 2.4.5 The WKB Method.- 2.5 Channel Waveguides.- 2.5.1 Channel Guide Geometries.- 2.5.2 The Vector Wave Equation.- 2.5.3 Numerical Analysis.- 2.5.4 Separation of Variables.- 2.5.5 The Method of Field Shadows.- 2.5.6 The Vector Perturbation Theorem.- 2.5.7 The Effective-Index Method.- 2.6 Coupled-Mode Formalism and Periodic Waveguides.- 2.6.1 Excitation of Waveguide Modes.- 2.6.2 Waveguide Deformations.- 2.6.3 Coupled-Wave Solutions.- 2.6.4 Periodic Waveguides.- 2.6.5 TE-to-TM Mode Conversion.- References.- 3. Waveguide Transitions and Junctions.- 3.1 Waveguide Modes and Coupled-Mode Theory.- 3.1.1 Normal Modes of Coupled Waveguides.- 3.1.2 Coupled-Mode Theory Representation.- 3.2 Fast and Slow Transitions.- 3.2.1 Local Normal Modes.- 3.2.2 Adiabatic Transition.- 3.2.3 Abrupt Transition.- 3.2.4 Tapered Velocity Coupler.- 3.2.5 3 dB Coupler.- 3.2.6 Directional Coupler.- 3.3 Mode Coupling Between Local Normal Modes.- 3.3.1 Coupled-Amplitude Equations.- 3.3.2 Differential Form of Coupled-Amplitude Equations.- 3.3.3 Coupled-Mode Theory Representation of Cij.- 3.4 Two-Arm Branches.- 3.4.1 Step Approximation for a Waveguide Branch.- 3.4.2 Analytic Solution for Shaped Branches.- 3.4.3 Experimental Results.- 3.4.4 Superposition of Solutions.- 3.5 Waveguide Horns.- 3.5.1 Mode-Conversion Coefficient cij for Channel Waveguides.- 3.5.2 Approximation for ??ij.- 3.5.3 Approximation for Cij.- 3.5.4 Parabolic Solution.- 3.6 Branches with Three Arms.- 3.6.1 Normal Modes of Three Coupled Waveguides.- 3.6.2 3×2 Waveguide Coupler.- 3.7 Conclusion.- References.- 4. Titanium-Diffused Lithium Niobate Waveguide Devices.- 4.1 Waveguide Fabrication.- 4.1.1 Titanium Diffused Waveguides.- 4.1.2 Proton Exchange LiNbO3 Waveguides.- 4.1.3 Post-Waveguide Processing.- 4.2 Basic Device Considerations.- 4.2.1 Electro-Optic Effect.- 4.2.2 Phase Modulator.- 4.2.3 Insertion Loss.- 4.2.4 Voltage/Loss Tradeoffs: Waveguide Tailoring.- 4.3 Switch/Modulator.- 4.3.1 Directional Coupler.- 4.3.2 Balanced-Bridge Interferometer.- 4.3.3 Intersecting-Waveguide Switch.- 4.4 On/Off Modulators.- 4.4.1 F-Branch Interferometer.- 4.4.2 Voltage and Bandwidth Consideration for Switch/Modulators.- 4.5 Polarization Devices.- 4.5.1 TE ? TM Conversion.- 4.5.2 Polarization Controller.- 4.5.3 Polarization-Selective Devices.- 4.6 Wavelength Filters.- 4.6.1 Interferometrie Filters.- 4.6.2 Coupled-Mode Filters.- 4.7 Polarization-Insensitive Devices.- 4.8 Some Ti:LiNbO3 Integrated-Optic Circuits.- 4.8.1 Coherent Lightwave Receiver.- 4.8.2 Optical Switch Arrays.- 4.9 Applications.- 4.9.1 External Modulators.- 4.9.2 High-Speed Analog to Digital Conversion.- 4.9.3 Fiber Gyroscope Chip.- References.- 5. Mode-Controlled Semiconductor Lasers.- 5.1 Organization of the Chapter.- 5.1.1 Notation.- 5.2 Laser Basics.- 5.2.1 Epitaxial Materials and Heterostructure.- 5.2.2 Waveguide Propagation, Amplification and Oscillation.- 5.2.3 Laser Gain.- 5.2.4 Spontaneous Emission.- 5.2.5 Photon Rate Equation.- 5.2.6 Spectral Hole Burning.- 5.2.7 Carrier Injection in a Heterojunction.- 5.2.8 Modal Rate Equations.- 5.2.9 Longitudinal Variation of Photon Density.- 5.2.10 Steady-State Solution of Rate Equations.- 5.2.11 Measurement of Modal Reflectivity and Laser Gain.- 5.3 Structures for Transverse-Mode Control.- 5.3.1 Stripe Geometry Laser, Blocking Layer.- 5.3.2 Buried Heterostructure Lasers.- 5.3.3 Ridge Waveguide Lasers.- 5.4 Longitudinal Mode Control.- 5.4.1 Three- and Four-Mirror Resonators.- 5.4.2 Distributed Bragg Gratings.- 5.4.3 Semiconductor DFB Lasers.- 5.4.4 DBR and Phase-Slip DFB Lasers.- 5.5 Linewidth.- 5.5.1 Linewidth of Fabry-Perot Laser.- 5.5.2 Linewidth Reduction Using Extended Cavities.- 5.6 High-Speed Modulation.- 5.6.1 Modulation Response.- 5.6.2 Origin of Chip Parasitics.- 5.6.3 Evaluation of Parasitics.- 5.6.4 Dependence of Parasitics on Device Structure.- 5.6.5 The Intrinsic Laser — Small-Signal Intensity Modulation Response.- 5.6.6 High-Frequency Limitations.- 5.6.7 Design Considerations for Wideband Lasers.- 5.6.8 Large-Signal Modulation — PCM.- 5.6.9 Large-Signal Modulation — Gain Switching.- 5.6.10 Active Mode-Locking.- 5.7 Luminescent Diodes and Laser Amplifiers.- 5.7.1 Edge-Emitting and Superluminescent Diodes.- 5.7.2 Linear Amplification and Amplified Spontaneous Emission in TWAs and ELEDs.- 5.7.3 Fabry-Perot Amplifiers and ELEDs.- 5.7.4 Amplifier Gain Compression.- 5.7.5 Amplifier Chain in Network Applications.- 5.7.6 Receiver Noise.- Appendix 5A: Glossary of Symbols.- References.- 6. Semiconductor Integrated Optic Devices.- 6.1 Semiconductor Waveguide Theory.- 6.1.1 Methods of Index Change in Semiconductors.- 6.1.2 Slab Waveguides.- 6.1.3 Channel Waveguides.- 6.1.4 Coupling Effects.- 6.1.5 Optical Loss.- 6.1.6 Curvature Loss.- 6.2 Material Technology.- 6.2.1 Liquid Phase Epitaxy (LPE).- 6.2.2 Vapor Phase Epitaxy (VPE).- 6.2.3 Metal Organic Chemical Vapor Deposition (MOCVD).- 6.2.4 Molecular Beam Epitaxy (MBE).- 6.2.5 Summary.- 6.3 Passive Waveguide Devices — Fabrication and Characterization.- 6.3.1 Channel Waveguides.- 6.3.2 Couplers.- 6.3.3 Bends and Branches.- 6.3.4 Grating Filter.- 6.4 Electro-Optic Guided-Wave Modulators — Theory.- 6.4.1 Electro-Optic Effect in III–V Semiconductors.- 6.4.2 Modulator Design.- 6.4.3 Modulation Frequency Analysis.- 6.4.4 Traveling-Wave Phase Modulators.- 6.4.5 TE-TM Coupling Analysis.- 6.4.6 Infrared Waveguide Modulators — Wavelength Scaling.- 6.4.7 Electro-Absorption Modulation.- 6.4.8 Carrier-Injection Modulator.- 6.4.9 Nonlinear Waveguide Modulator.- 6.5 Electro-Optic Guided-Wave Modulator Characteristics.- 6.5.1 Phase Modulators.- 6.5.2 Directional-Coupler Switches.- 6.5.3 Interferometrie Modulators.- 6.5.4 Integrated Waveguides/Optoelectronics/Electronics.- 6.5.5 Electro-Absorption Modulators.- 6.5.6 Multiple-Quantum-Well Modulators.- 6.5.7 Nonlinear Waveguide Modulators.- 6.6 Optoelectronic Integrated Circuits (OEIC).- 6.7 Concluding Remarks.- References.