UBCx Phot1x: Silicon Photonics Design, Fabrication and Data Analysis

Transcription

1 UBCx Phot1x: Silicon Photonics Design, Fabrication and Data Analysis Course Syllabus Table of Contents Course Syllabus 1 Course Overview 1 Course Learning Objective 1 Course Philosophy 1 Course Details 1 During the course, you will 2 Comments about the fabrication 2 Fabrication details: 2 Course Schedule 3 Weekly schedule 3 Grading 5 Assignments 5 Appendix course change log & history 5 Course Overview Course Learning Objective This course will help you complete a silicon photonics design-fabricate-test cycle. Course Philosophy This course offered is a highly compressed design cycle only 4 weeks of design, as opposed to 6-12 months typical in silicon photonics foundry fabrication. The philosophy is that a participant should see the complete design cycle first, and as quickly as possible. Once familiar with the tools, techniques, challenges, limitations, and opportunities, the participant will be in a much stronger position to dedicate more time for a complex design. Course Details This short course teaches participants (industry professionals, academics) how to design passive silicon photonic devices using analytic and advanced numerical techniques. Your designs will be fabricated by a state-of-the-art rapid-prototyping 100 kev Electron-Beam Lithography (EBL) facility (University of Washington Washington Nanofabrication Facility, USA, and/or Applied Nanotools Inc. Canada). All designs will be tested using an automated optical probe station (University of British Columbia, Canada) and the data provided to the participants. You will then analyze your experimental data. This short course is a highly compressed version of the SiEPIC CMC Passive Silicon Photonics Fabrication workshop several hours versus 6 days of instruction; a seven-week versus a one-year design-fabricate-test cycle; and a total minimum time commitment of only 20 hours. 1

2 The focus of this course is a design project, guided by lectures, tutorials and activities. As a first-time designer, you will design an interferometer, which is a widely used device in many applications such as communications (modulation, switching) and sensing. Specifically, it is Mach-Zehnder Interferometer, consisting of fibre grating couplers, two splitters, and optical waveguides. For advanced designers, this course is an opportunity to design many other devices, such as directional couplers; ring, racetrack and disk resonators; Bragg gratings, including grating assisted contra-directional couplers; photonic crystals; multi-mode interference (MMI) couplers; arrayed waveguide gratings (AWG); polarization diversity components; mode-division multiplexing (MDM) components and circuits; and novel waveguides such as sub-wavelength grating (SWG) waveguides and slot waveguides. During the course, you will 1. Learn the operating principles of the silicon photonic interferometer. The example we use is a Mach-Zehnder interferometer consisting of two fibre grating couplers, two Y-branch splitters, and optical waveguides. 2. Model the optical waveguide using a mode solver to determine the wavelength-dependent effective index and propagation constant. These parameters will be used in the circuit model. 3. Model a silicon photonic optical circuit using a compact model approach. We will simulate the optical transmission spectrum of the circuit (transmission versus wavelength), for several substrate temperatures. 4. Design photonic components and circuits, e.g., interferometer. Identify design parameter variations. 5. Create and submit a layout for fabrication. Learn the fabrication design rules, automated testing constraints, and design submission details. 6. Understand how silicon photonic devices are fabricated and the manufacturing challenges, including, variability, impact on devices/circuits and computational lithography models. Learn how to design for variability through the use of corner and Monte-Carlo analysis. 7. Conduct a design review on three other peoples' designs, and receive feedback. 8. Receive measurement data from fabricated devices. Analyze the data to extract parameters from the measurements and compare with models. Report on your design results. Comments about the fabrication You will have four weeks to complete your design. You will use an online tool to conduct design reviews of your peers. Your layouts will be merged onto a single chip and fabricated. The design file for the entire chip is shared with the group. All designs will be tested using an automated silicon photonic probe station Measurement results (e.g., 10,000 point spectra centered at 1550 nm) will be provided. Fabrication details: Silicon on insulator (SOI) wafer with 220 nm silicon thickness Single full-etch, 82º sidewall angle, and minimum isolated feature size of 60 nm. More details at R. Bojko, et al., JVSTB, Each participant will receive an area of 605 µm (width) X 410 µm (height), enough for >10 devices (more available on request). Basic components provided as a GDS library: focusing sub-wavelength grating couplers (TE or TM, 1550 nm), Y-Branch and other splitters, waveguides and routing, waveguide Bragg gratings, ring resonator, example layouts. Fabrication cost - included. 2

3 Course Schedule Live Q&A sessions will typically be held on Mondays at 18:00 UTC. Invited lectures / webinars will be scheduled throughout the class. All lessons are released on Tuesdays. All assignments are due on Monday of the following week. Only the major assignments are listed in the table below. There are minor on-line questions throughout. Please check the exact time in Courseware. Note that the dates are in the UTC time zone. Weekly schedule Week Section 0 Introduction: Course & Project Overview What is Silicon Photonics? Software Installation MATLAB Tutorials 1 Photonic Components: Introduction to Optical Waveguides, SOI Wafers and Optical Materials (Refractive Index & Group Index) Waveguide Types, Slab and Strip Waveguides, Optical loss, Effective index method Waveguide Modelling: 2D Eigenmode Solver (MATLAB), Lumerical MODE, Waveguide effective index, Group index, Compact Model, Optional: Temperature Dependence, Convergence Tests, Mode Area & Confinement Factor Y-Branch: Beam splitter and Silicon Photonic Y-Branch principles, FDTD Simulations Waveguide Bends: Sources of loss (mode-mismatch and radiation), what bend radius can be used, simulation of bent mode profiles Fibre Grating Coupler: Operating principle, simulation using FDTD, Subwavelength grating couplers, experimental results [Optional] Advanced Components: Directional couplers: Waveguide Bragg gratings; Contra-directional grating couplers; Sub-wavelength grating (SWG) waveguides; Sub-wavelength grating (SWG) fibre grating couplers (FGC); Evanescent field sensors; Multi-mode interference (MMI) couplers; Polarization Splitter Rotators. 2 Photonic Circuits: Interferometers Photonic Circuit Modeling and Circuit Simulation Tools Interferometer Types (Mach-Zehnder and Michelson), Balanced vs. imbalanced, Applications Modeling Lumerical INTERCONNECT: Types of problems that can be solved, importing the Y-Branch component, building the interferometer and calculating the transmission, adding fibre-grating couplers (S-Paramaters), modeling temperature dependence Compact Model Libraries: Photonic circuit simulation challenges, building photonic component compact models, circuit simulations, compact models (S- Parameters) Building interferometer circuits, adjustable splitters, lattice filters, (optional) building a race-track / ring resonator Photonic Circuits: Draft Design Report 3 Layout For Fabrication: GDS Fundamentals Process Design Kits: fabrication process summary, layout layers and design rules 3

4 Component Library: component layouts, experimental results, publications describing components Layout requirements for automated testing, design for test. Layout KLayout (Bottom-up): Introduction, Layout of an MZI, Layout verification, Circuit simulations from Layout, Hierarchical layout, Scripted Layout Schematic Driven Design: Advanced design methodology: Schematic-Driven Layout using Mentor Graphics, Schematic & Simulation, Schematic-Driven Layout, Layout Versus Schematic (LVS), Post-Layout Simulation, Design Variations & Hierarchy, Exporting GDS, Scripting & PCells Design Review: Layout Verification Design review concepts; Design review checklist (design concept, manufacturability, mask layout, design for test, submission details); Automated layout verification Layout For Fabrication: Draft Layout Submission 4 Design Review: Submission into Peer Assessment Design Review: Peer Assessment Layout For Fabrication: Final Layout Submission 5 Fabrication: Electron Beam Lithography: Fundamentals, Silicon photonic waveguide fabrication steps, Manufacturing Challenges: Wafer thickness and feature size variability, Impact on devices, Smoothing and computational lithography models, Modelling with variability, Corner analysis, (optional) Monte-Carlo Simulations 6 Measurement Data Analysis: Practice Measurement Data and Analysis: Analyzing experimental data (particularly MZI s), extracting useful waveguide parameters from data, comparing experimental data with simulations Baseline corrections: Curve-fit with a polynomial, Loopback structures Fitting the MZI: Curve fitting with the MZI transfer function, Curve fitting using find-peaks, Fitting with autocorrelation Measurement vs. simulation (Optional) Data analysis using Python 7 Your Design, Measured: Measurement data, Measurement vs. simulation: Apply measurement data analysis techniques on your own experimental data: Extract circuit and component parameters, Compare with simulations SEM and Fabrication Metrology Compare extracted waveguide parameters (group index) with rest of class Assess whether data falls within corner analysis Final Report Final Exam 4

5 Grading This course is graded as follows: 50% Mini-homework questions embedded within the units, answered and graded in the web browser. 10% Design review score: peer evaluation based on the PDF report and GDS layout. 20% Analysis: comparison of experiments vs. simulation; experimental data should lie within the range of simulated results considering manufacturing variability. 20% Final Report 10% bonus Final exam Grade required to pass the course: 70% Assignments Photonic Components Week 1 Simulation of photonic components. Mainly numerical answers. Photonic Circuits Week 2 Simulation of photonic circuits. Mainly numerical answers. The first part of optical design consists of learning how to simulate optical components and optical circuits. The second part is to choose the device and circuit parameters to meet your design specifications. Assignment Write and submit a PDF report describing your design Layout Week 3 Assignment Create and submit a layout for your design Design Review Week 4 Assignment Provide feedback to your peers. Receive feedback. Update your design and layout, and submit. Fabrication Week 5 Assignment Update your models to include manufacturing considerations. Measurement Data Analysis Week 6 Assignment Practice data analysis. Your Design, Measured Week 7 Assignment Analyze your experimental data. Write and submit a final PDF report. Final Exam Week 7 Answer questions. Appendix course change log & history 2016_T3: November 2016 Additional units & activities in Photonic Circuits (Adjustable splitter MZI; Lattice FIR filter MZI) 2016_T1: April 2016 KLayout SiEPIC-EBeam PDK with waveguide generation, Netlist extraction from physical layout, circuit simulations using INTERCONNECT, Monte-Carlo simulations Additional Optional content without videos directional couplers, ring resonators, Bragg gratings. 2015_T3: November 2015 Improvements 2015_T2: July 2015 Initial offering 5