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Multi-Mode and Single Mode Polymer Waveguides and Structures for Short-Haul Optical Interconnects

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Multi-Mode and Single Mode Polymer Waveguides and Structures for Short-Haul Optical Interconnects Michigan Technological University Digital Commons @ Michigan Tech Dissertations, Master's Theses and Master's Dissertations, Master's Theses and Master's Reports - Open Reports 2015 MULTI-MODE AND SINGLE MODE POLYMER WAVEGUIDES AND STRUCTURES FOR SHORT-HAUL OPTICAL INTERCONNECTS Kevin L. Kruse Michigan Technological University Follow this and additional works at: https://digitalcommons.mtu.edu/etds Part of the Communication Commons, Optics Commons, and the Polymer Chemistry Commons Copyright 2015 Kevin L. Kruse Recommended Citation Kruse, Kevin L., "MULTI-MODE AND SINGLE MODE POLYMER WAVEGUIDES AND STRUCTURES FOR SHORT-HAUL OPTICAL INTERCONNECTS", Dissertation, Michigan Technological University, 2015. https://doi.org/10.37099/mtu.dc.etds/977 Follow this and additional works at: https://digitalcommons.mtu.edu/etds Part of the Communication Commons, Optics Commons, and the Polymer Chemistry Commons MULTI-MODE AND SINGLE MODE POLYMER WAVEGUIDES AND STRUCTURES FOR SHORT-HAUL OPTICAL INTERCONNECTS By Kevin L. Kruse A DISSERTATION Submitted in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY In Electrical Engineering MICHIGAN TECHNOLOGICAL UNIVERSITY 2015 © 2015 Kevin L. Kruse This dissertation has been approved in partial fulfillment of the requirements for the Degree of DOCTOR OF PHILOSOPHY in Electrical Engineering. Department of Electrical and Computer Engineering Dissertation Advisor: Dr. Christopher Middlebrook Committee Member: Dr. Michael Roggemann Committee Member: Dr. Durdu Guney Committee Member: Dr. Craig Friedrich Department Chair: Dr. Daniel R. Fuhrmann To Lee & Diane Kruse Table of Contents List of Figures ................................................................................................................... ix Preface ............................................................................................................................. xix Acknowledgements ........................................................................................................ xxi Abstract .......................................................................................................................... xxii Chapter 1: Optical Interconnects .....................................................................................1 1.1. Introduction ...............................................................................................................1 1.2. Electrical Interconnects .............................................................................................2 1.3. Optical Interconnects ................................................................................................4 1.3.1 Optical Fibers .....................................................................................................5 1.3.2. Rectangular Waveguides ...................................................................................7 1.3.3. Silicon Photonics ...............................................................................................9 1.4. Research Outline .......................................................................................................9 Chapter 2: Polymer Waveguide Theory ........................................................................15 2.1. Introduction .............................................................................................................15 2.2. Propagation Theory .................................................................................................16 2.2.1. Ray Tracing Method ........................................................................................16 iv 2.2.2. Electromagnetic Model ....................................................................................18 2.3. Propagation Loss .....................................................................................................21 2.3.1. Material Loss ...................................................................................................22 2.3.2. Surface Loss .....................................................................................................22 2.4. Geometric Structure Loss .......................................................................................23 2.4.1. Radial Loss.......................................................................................................24 2.4.2. Transition Loss.................................................................................................26 2.4.3. Total Structure Loss .........................................................................................27 2.5. Dielectric WG Model and Simulation Methods .....................................................28 2.5.1. Effective Index Method ....................................................................................28 2.5.2. Finite Difference Time Domain .......................................................................30 2.5.3. Beam Propagation Method ..............................................................................32 2.5.4. Mode Solvers ....................................................................................................33 2.6. Conclusion ..............................................................................................................36 Chapter 3: Waveguide Fabrication and Evaluation .....................................................37 3.1. Introduction .............................................................................................................37 3.2. Dielectric WG Materials .........................................................................................38 3.3. Fabrication Procedures ............................................................................................39 3.3.1. Photolithography .............................................................................................41 v 3.4. Testing and Evaluation ...........................................................................................44 3.4.1. Refractive Index Testing ..................................................................................45 3.4.2. End-fire Coupling Method ...............................................................................46 3.4.3. Cut-back Method ..............................................................................................48 3.4.4. Signal Quality Analysis ....................................................................................50 3.5. Fabrication Summary ..............................................................................................51 Chapter 4: Laser Direct Write Method .........................................................................53 4.1. Introduction .............................................................................................................54 4.2. Theoretical Model ...................................................................................................56 4.3. Experimental Setup Procedure ................................................................................58 4.4. Results and Discussion ...........................................................................................64 4.4.1. LDW WG Dimensions ......................................................................................65 4.4.2. LDW MM & SM WG Straights ........................................................................68 4.4.3. LDW SM & MM WG Radial Bends .................................................................70 4.4.4. LDW WG Crossings .........................................................................................71 4.5. LDW Conclusion ....................................................................................................74 Chapter 5: SM WG S-Bends and Splitters ....................................................................76 5.1. Introduction .............................................................................................................77 5.2. Design and Theoretical Loss ...................................................................................80 vi 5.3. S-Bend Fabrication .................................................................................................85 5.4. Photolithographic Results .......................................................................................87 5.4.1. Photolithographic SM WG S-Bends.................................................................87 5.4.2. S-Bend Splitters ................................................................................................89 5.4.3. Laser Direct Written SM WG S-Bends.............................................................93 5.4.4. S-Bend Foot-print Requirements .....................................................................97 5.5. SM WG S-Bend Conclusion .................................................................................100 Chapter 6: Polymer WG Tapers ..................................................................................102 6.1. Introduction ...........................................................................................................102 6.2. Polymer WG Taper Theory and Designs ..............................................................106 6.2.1. Taper Theory ..................................................................................................106 6.2.2. Taper Design ..................................................................................................109 6.3. WG Taper Simulation
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