vii TABLE OF CONTENTS CHAPTER 1 2 TITLE PAGE DECLARATION ii DEDICATION iii ACKNOWLEDGEMENT iv ABSTRACT v ABSTRAK vi TABLE OF CONTENTS vii LIST OF TABLES x LIST OF FIGURES xii LIST OF ABBREVIATIONS xvii LIST OF SYMBOLS xviii LIST OF APPENDICES xxi INTRODUCTION 1 1.1 Research Background 1 1.2 Problem Statement 2 1.3 Research Objectives 3 1.4 Research Scope 4 1.5 Research Significance 5 1.6 Thesis Outline 5 LITERATURE REVIEW OF OPTICAL BISTABILITY 7 2.1 Introduction 7 2.2 Optical Bistability Switching 7 2.3 Optical Bistability in MRR 19 viii 3 4 THEORY OF OPTICAL BISTABILITY 25 3.1 Introduction 25 3.2 Nonlinear Response of Optical Fiber 25 3.3 Nonlinear Refraction 28 3.4 Self-phase Modulation 29 3.5 Group Velocity Dispersion 30 3.6 Temporal Optical Soliton 32 3.7 Microring Resonator 37 3.8 Mobius Resonator Configuration 38 3.9 Coupling Theory 43 3.10 Transfer Matrix Analysis 50 3.11 Optical Bistability 52 RESEARCH METHODOLOGY 58 4.1 Introduction 58 4.2 Mathematical Computation of Optical Fields in MRR 4.3 5 59 4.2.1 All-pass Type MRR Configurations 59 4.2.2 Add-drop Type MRR Configurations 65 4.2.3 PANDA Type MRR Configurations 71 Modelling of Microring Resonator System 79 4.3.1 Modelling of All-pass MRR 80 4.3.2 Modelling of Add-drop MRR 84 4.3.3 Modelling of PANDA MRR 88 RESULTS AND DISCUSSIONS 91 5.1 Introduction 91 5.2 Analysis of Optical Bistability in All-pass Type MRR Configurations 5.2.1 92 Analysis of Output Power of All-pass and All-pass Mobius MRR 93 ix 5.2.2 Optical Hysteresis Operating in All-pass and All-pass Mobius Configurations 5.2.3 96 Parametric Effects of Optical Bistability in All-pass Type MRR Configurations 5.3 101 Analysis of Optical Bistability in Add-drop Type MRR Configurations 5.3.1 110 Analysis of Output Power of Add-drop Filter and Add-drop Mobius MRR 5.3.2 110 Optical Hysteresis Operating in Add-drop and Add-drop Mobius MRR Configurations 5.3.3 113 Parametric Effects of Optical Bistability in Add-drop Type MRR Configuration 5.4 118 Analysis of Optical Bistability in PANDA Type MRR Configurations 5.4.1 129 Analysis of Output Power of PANDA and PANDA Mobius MRR 5.4.2 129 Optical Hysteresis Operating in PANDA and PANDA Mobius MRR Configurations 5.4.3 133 Parametric Effects of Optical Bistability in PANDA Type MRR Configuration 5.5 Optimization and Switching of Optical Bistability in Mobius-Type MRR 6 141 164 CONCLUSION 171 6.1 Conclusion 171 6.2 Future Work 173 REFERENCES Appendices A-D 174 184 - 208 x LIST OF TABLES TABLE NO. TITLE PAGE 5.1 5.2 5.3 5.4 5.5 5.6 5.7 The threshold powers, output switch powers, and hysteresis widths of the optical bistability loops at output port, point 1, and point 2 for the All-pass Mobius configuration 100 List of threshold powers, output switch powers, and hysteresis widths of the optical bistability loops with variation of radius, and coupling for All-pass and Allpass Mobius configurations 108 List of threshold powers, output switch powers, and hysteresis widths of the optical bistability loops with variation of control power for All-pass and All-pass Mobius configurations 109 The threshold powers, output switch powers, and hysteresis widths of the optical bistability loops at output ports, point 1, point 2, point 3 and point 4 for the Add-drop filter ADF and Add-drop Mobius ADM configurations. 117 Threshold powers, output switching powers ΔPswitch, and hysteresis width Whys for Add-drop Mobius and Add-drop filter configurations as a function of radius, coupling coefficients and control powers. 128 Threshold powers, output switch powers, and hysteresis widths of the optical bistability loops for optical power at output port, point 1, 2, 3, and 4 of Allpass and All-pass Mobius configurations 140 List of threshold powers, output switch powers, and hysteresis widths of the optical bistability loops with variation of radius for PANDA and PANDA Mobius configurations 160 xi 5.8 5.9 5.10 List of threshold powers, output switch powers, and hysteresis widths of the optical bistability loops with variation of coupling coefficient for PANDA and PANDA Mobius configurations 161 List of threshold powers, output switch powers, and hysteresis widths of the optical bistability loops with variation of control power for PANDA and PANDA Mobius configurations 162 Optimized properties 168 Mobius types MRR configurations xii LIST OF FIGURES FIGURE NO. TITLE PAGE The relation between induced polarization P and electric field E 26 Schematics illustration of optical pulse with dispersive and SPM 33 3.3 All-pass microring resonator configuration 38 3.4 Add-drop ring resonator configuration 38 3.5 Schematics diagram of Mobius strip 39 3.6 Photograph of Mobius wire resonator comprise of 5.715 cm radius with 3.175 cm vertical height of aluminum cavity 40 3.7 Schematics diagram of Mobius resonator 40 3.8 Schematics diagram of transmission line comprised of inductors and capacitors components in rectangular loop arrangement 41 Schematics Mobius and ring resonator with the periodic elements of LC electrical circuit 41 Schematic diagram of fabrication process of microring waveguide in Mobius shape 42 3.11 Coupling between two parallel waveguides 44 3.12 Schematics diagram of transfer matrix method 51 3.13 Fabry-Perot interferometer with the unidirectional nonlinear cavity 54 The detuning of optical input source without increment of intensity 55 3.1 3.2 3.9 3.10 3.14 xiii 3.15 The output versus input intensity curve with zero phase detuning 56 The output versus input intensity curve with low phase detuning 56 The output versus input intensity curve with high phase detuning 57 4.1 Schematics diagram of All-pass MRR system 60 4.2 Schematic diagram of All-pass Mobius configuration 63 4.3 Schematics diagram of Add-drop MRR system 66 4.4 Schematics diagram of Add-drop Mobius ring resonator 69 4.5 PANDA configuration of MRR system 71 4.6 Propagation of electric field approaching the PANDA right side ring waveguide 73 Propagation of electric field approaching the PANDA left side ring waveguide 73 4.8 Schematics diagram of PANDA Mobius ring resonator 75 4.9 Right-side ring coupled to the centre PANDA Mobius configuration 77 Left-side ring coupled to the centre PANDA Mobius configuration 77 The modelling process of All-pass and All-pass Mobius configuration of MRR system 83 The modelling process of Add-drop and Add-drop Mobius configuration of MRR system 87 The modelling process of PANDA and PANDA Mobius configuration of MRR system 90 5.1 Optical Bright soliton signal spectrum 93 5.2 The optical power spectrum of all-pas and All-pass Mobius configuration, (a) and (b) are the power of circulated field at point 1 and point 2 respectively, c) is the output power of the microring system 95 Hysteresis loop of optical bistability behavior on All- 97 3.16 3.17 4.7 4.10 4.11 4.12 4.13 5.3 xiv pass and All-pass Mobius configuration MRR system 5.4 5.5 5.6 5.7 5.8 5.9 5.10 5.11 5.12 5.13 5.14 5.15 5.16 i) Schematic diagram All-pass and All-pass Mobius of ii)Circulated power at point 1 a) and 2 b) plotted with respect to input power 98 The input-output power relation of radius variation in All-pass configuration Ri where i= 1μm, 2μm, 3μm, 4μm, 5μm, and 6μm. 102 The output-to-input power relation of coupling coefficients variation κi where i=0.4, 0.5, 0.6, 0.7, 0.8, and 0.9 105 The output-to-input relation with the increment of input power Pin (in=50mW, 60mW, 70mW, 80mW, 90mW, and 100mW) variation 107 Optical powers generated at through (a) and drop (b) port of ADF and Add-drop-Mobius configurations 111 Optical circulation powers in ADF and ADM configurations at point 1, 2, 3, and 4 as (a) to (d) respectively 112 Hysteresis loop of optical bistability generated by using ADF and ADM configuration 114 Optical hysteresis loop of circulating power of ADF and ADM configurations 116 Output-to-input power relation of radius variation in ADF and ADM configurations Ri where i= 1μm, 2μm, 3μm, 4μm, 5μm, and 6μm 119 The output-to-input power relation of coupling coefficients variation κi in ADF and ADM configurations where i = 0.4, 0.5, 0.6, 0.7, 0.8, and 0.9 122 i) The output-to-input power relation of control power Pc variation in ADF and ADM configurations. ii) The hysteresis loop of the bistable signal in ADM MRR. 126 Optical transmission spectrum generated at output (a) and drop (b) ports of PANDA and PANDA M configurations 130 Optical circulation powers in PANDA and PANDAMobius configurations at point 1, 2, 3, and 4 as (a) to (d) respectively 132 xv 5.17 5.18 5.19 5.20 5.21 5.22 5.23 5.24 5.25 5.26 5.27 The output port optical power versus the input power in PANDA and PANDA M configuration 134 Circulation power hysteresis i) diagram of PANDA and PANDA M circulation point ii) Input-output power relation of circulating power at point 1,2,3 and 4 136 Optical bistability in increase of main ring radius PANDA configuration a) schematics of PANDA configuration with radius variation of 6 μm to 7μm b) Input-output power relation for 6 μm and c) Inputoutput power relation for 7 μm 142 Output-to-input power relation of PANDA configuration with radius variation for 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, and 11 μm a) to f). 143 Optical bistability in increase of main ring radius PANDA Mobius configuration a) schematics of PANDA Mobius configuration with radius variation of 6 μm to 7μm b) Input-output power relation for 6 μm and c) Input-output power relation for 7 μm 145 Output-to-input power relation of PANDA Mobius configuration with radius variation for 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, and 11 μm 146 Output-to-input power relation of a) PANDA Mobius and b) PANDA configurations with 0.4 and 0.5 coupling coefficients 150 Output-to-input power relation of PANDA and PANDA Mobius configurations with coupling coefficients variation for 0.4, 0.5, 0.6, 0.7, 0.8, and 0.9 151 PANDA control power variation i) schematic diagram of PANDA configurations with control power variation of 50mW to 60mW, ii) Input-output power relation with 50mW and 60mW power variation 153 PANDA Mobius control power variation i) schematic diagram of PANDA Mobius configurations with control power variation of 50mW to 60mW, ii) Input-output power relation with 50mW and 60mW power variation 155 Output-to-input power relation of PANDA and PANDA Mobius configurations with coupling coefficients variation for 50 mW, 60 mW, 70 mW, 80 mW, 90 mW, and 100 mW 157 xvi 5.28 5.29 5.30 The output port optical power versus the input power for All-pass, Add-drop, and PANDA types MRR configuration 165 The switching operation of optical bistability hysteresis loop using All-pass Mobius MRR configuration 166 Optical bistability from the simulated All-pass Mobius MRR, experimental data of conventional All-pass MRR, and finite-element-method (FEM) simulation of single MRR system. 169 xvii LIST OF ABBREVIATIONS MRR - Microring Resonator FDTD - Finite-Different-Time-Domain SPR - Surface Palsmon Resonance VCSEL - Vertical Cavity Surface Emitting Laser EDF-FBG - Erbium Doped Fiber-Fiber Bragg Grating FBG - Fiber Bragg Grating SMFPLD - Single Mode of Fabry Perot Laser Diode EIR - Induced Reflection Effect WGM - Whispering Gallery Mode NLC - Nematic Liquid Crystal PHI - Photo Induced Isotropic ICP - Inductively Plasma Coupled SEM - Scanning Electron Microscopy All-pass M - All-pass Mobius Add-drop M - Add-drop Mobius PANDA M - PANDA Mobius xviii LIST OF SYMBOLS ε0 - Electric vacuum permittivity χ - Electric susceptibility α - Attenuation loss P - Polarization PNL - Nonlinear polarization c - Speed of light n - Internal refractive index ω0 - Angular frequency E - Electric field Po - Nonlinear angular frequency t - Propagation time Χ(i) - ith order of susceptibility χeff - Effective susceptibility n0 - Linear refractive index k0 - Wavenumber L - Propagation length I - Intensity 𝜙L - Linear phase shift 𝜙NL - Nonlinear phase shift λ - Wavelength β - Propagation constant T - Pulse propagation time vg - Group velocity β2 - Group velocity dispersion parameter ΔT - Pulse spreading time LD - Dispersion length xix T0 - Pulse width A - Pulse amplitudes a(t,z) - Pulse envelope f(x,y) - Spatial structure of optical field β(ω) - Phase constant βnl - Nonlinear phase constant βl - Linear phase constant Io - Pulse propagation time z - Pulse propagation distance in z direction LNL - Nonlinear length η0 - Wave impedance In - Current amplitude N - Number of ladder circuit L’ - Inductance C’ - Capacitance M - Mutual impedance k - Wavevector n2’ - Waveguide 2 refractive index n1 - Waveguide 1 refractive index μo - Vacuum permeability S1 - Complex amplitude u - Wave amplitude function C21 - Coupling coefficient waveguide 1 to 2 iS - Cross coupling parameter C - Self-coupling parameter T’ - Transmission coefficient R’ - Reflection coefficient 𝜙H - High negative detuning 𝜙L - Low negative detuning 𝜙0 - Centre detuning κi - Coupling coefficient at coupling region i n2 - Nonlinear index Aeff - Effective area xx Ei - Electric field at i position Eim - Electric field at i position for Mobius resonator ξi - Phase shift for i radius 𝛾i - Propagation loss at coupling region i Aeff - Effective area xxi LIST OF APPENDICES APPENDIX TITLE PAGE A All-pass and All-pass Mobius Coding 184 B Add-drop and Add-drop Mobius Coding 192 C PANDA and PANDA Mobius Coding 197 D Threshold Determination Graph 208