Table Of ContentSynthesis Lectures on Digital Circuits &
Systems
SeriesEditor
MitchellA.Thornton,SouthernMethodistUniversity,Dallas,USA
This series includes titles of interest to students, professionals, and researchers in the
areaofdesignandanalysisofdigitalcircuitsandsystems.EachLectureisself-contained
andfocusesonthebackgroundinformationrequiredtounderstandthesubjectmatterand
practical case studies that illustrate applications. The format of a Lecture is structured
such that each will be devoted to a specific topic in digital circuits and systems rather
thanalargeroverviewofseveraltopicssuchasthatfoundinacomprehensivehandbook.
The Lectures cover both well-established areas as well as newly developed or emerging
material in digital circuits and systems design and analysis.
Ahmadreza Farsaei
Introduction to Layout
Design and Automation
of Photonic Integrated
Circuits
AhmadrezaFarsaei
LuDALogLLC
SanJose,CA,USA
ISSN1932-3166 ISSN1932-3174 (electronic)
SynthesisLecturesonDigitalCircuits&Systems
ISBN978-3-031-25287-7 ISBN978-3-031-25288-4 (eBook)
https://doi.org/10.1007/978-3-031-25288-4
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2023
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Tomyparentswhoaremyroots
FormywifeNiloofarandchildrenNickandRumi
whoarethesourceofmyhope
Preface
Silicon photonics is a promising platform and technology whose application covers not
only high-speed communication links used in data centers, but also novel applications in
biological sensing, Light Detection and Ranging (LiDAR), and co-packed optics [1, 2].
The design complexity of Photonic Integrated Circuits (PICs) supporting these applica-
tions has been significantly increased both in terms of architecture and the number of
device instances used to create the final mask layout. PIC designs’ evolving complexity
requires a unified and salable design automation solution to address their unique chal-
lenges.Althoughtherehavebeenmanytextbooks[3]onfundamentalconceptsandbasic
physics of silicon photonics, there is not a body of literature providing proper education
on PIC design automation.
There are three main challenges that an Electronic Photonic Design Automation
(EPDA)solutionshouldaddress[4–6]:(1)Implementationofphotoniccomponents’com-
plex curvilinear shapes, (2) Enabling a unified electro-optical co-simulation flow, (3)
Native support for physical verification and extraction of complex curvilinear shapes.
In this book, I am mainly focused on the implementation of complex photonic compo-
nents’ curvilinear shapes. Traditional Electronic Design Automation (EDA) solutions are
based on supporting rectilinear/octilinear concepts. This implies that these solutions are
not capable of reliably supporting complex curvilinear shapes required to implement a
photonic component’s mask layout. Proper implementation of an EPDA solution should
be derived from an EDA solution with an additional mathematical engine to: (1) Capture
curvilinear shapes using parametric mathematical equations, (2) Manipulate curves and
extractcurves’characteristics,(3)providerequiredsoftwareconstructstorepresentapho-
tonic device using parametric mathematical equations, and (4) establish a link between
mathematical domain and discretized polygon domain for the final generation of mask
layout.
The book comprises six chapters that are structured to be very concise, practical, and
example-driven. The content of each chapter is chosen carefully and is based on the
training I have had for professional and industry experts. Each chapter starts with a main
concept and continues with code examples and use cases to support that concept. Each
chapteriswritteninsuchawaythatyoushouldbeabletoreadandcomprehendthemain
vii
viii Preface
concept,andwriteandtestcodeexamplesinaday.Ihaveincludedsomeexercisesinside
each chapter so that you can evaluate your progress and understanding of the concepts.
Chapters 1–3 are mainly focused on photonic devices’ physical implementation and
introduction to Virtuoso® CurvyCoreTM Application Programming Interfaces (APIs).
Chapter 4 is focused on the Parameterized Cell (PCell) concept and implementation as
well as some fundamental concepts behind a hierarchical design methodology such as
terminals,pins,instanceterminals,etc.Chapter5isfocusedonhowtosolvesomedesign
problems by SKILL®TM scripting. I have included Chap. 6 to introduce proper scalable
software development methodology using SKILL++.
Virtuoso is the tool used for the implementation of my designs and the Virtu-
oso CurvyCore mathematical engine is used to implement photonic devices’ physical
design (layout). SKILL is the main scripting language used for code implementation.
All the examples provided in the book are based on Generic Optical Process Design Kit
(GoPDK), which is a generic optical PDK developed by Cadence Design Systems, Inc.
to demonstrate their photonic solution capabilities.
In this book, I have assumed you have basic knowledge of algorithm, software devel-
opment, data structures, and SKILL programming. Although deep knowledge of using
Virtuoso design suites such as Virtuoso Layout and Schematic Suites is not needed, you
shouldbefamiliarwithhowtoperformsomebasictaskssuchascreateanewlibraryand
cellviews.AlthoughyoucanuseanyeditortowriteyourSKILLprograms,Irecommend
youbecomefamiliarwithSKILLIntegratedDevelopmentEnvironment(IDE)toenhance
the productivity and efficiency of your software development cycle.
Whowouldbenefitfromthisbook?Ihavewrittenthisbookwithtwotargetaudiences,
academia and industry, in mind. Academia: any senior undergraduate/graduate student
pursuing a career in integrated photonics. Industry: PIC circuit and mask designers, PIC
component developers, Process Design Kit (PDK) developers, and PIC Computer-Aided
Design (CAD) engineers.
San Jose, USA Ahmadreza Farsaei
November 2022
References
1. S.Tanaka,T.Akiyama,S.Sekiguchi,andK.Morito,“Siliconphotonicsopticaltransmittertech-
nologyfortb/s-classi/oco-packagedwithcpu,”FujitsuSci.Tech.J,vol.50,no.1,pp.123–131,
2014.
2. C.V.Poulton,A.Yaacobi,D.B.Cole,M.J.Byrd,M.Raval,D.Vermeulen,andM.R.Watts,
“Coherentsolid-statelidarwithsiliconphotonicopticalphasedarrays,”Optics letters,vol.42,
no.20,pp.4091–4094,2017.
3. A.YarivandP.Yeh,Photonics:opticalelectronicsinmoderncommunications.1emplus0.5em
minus0.4emOxforduniversitypress,2007.
Preface ix
4. G. Lamant, J. Flueckiger, F. Villa, A. Farsaei, B. Wang, R. Stoffer, X. Wang, J. Pond, and T.
Korthorst,“Schematicdrivensimulationandlayoutofcomplexphotonicic’s,”in2016IEEE13th
International Conference on Group IV Photonics (GFP).1emplus0.5emminus0.4emIEEE,
2016,pp.92–93.
5. J.Pond,X.Wang,Z.Lu,E.Schelew,G.Lamant,andA.Farsaei,“Latestadvancementstothe
industry-leadingepdadesignflowforsiliconphotonics,”in2019IEEE/ACMInternationalCon-
ferenceonComputer-AidedDesign(ICCAD).1emplus0.5emminus0.4emIEEE,2019,pp.1–
6.
6. J. Pond, G. S. Lamant, and R. Goldman, “Software tools for integrated photonics,” in Optical
FiberTelecommunicationsVII.1emplus0.5emminus0.4emElsevier,2020,pp.195–231.
Acknowledgments
I have been teaching in academia and educating industry experts on the domain of Elec-
tronicPhotonicDesignAutomation(EPDA)formanyyearsthroughdifferentvenuessuch
as workshops and conferences. Their feedback established the need for a more practical
and educational solution for this new domain in my mind. I am very thankful to all of
them for their feedback and motivation. Among them are Shahriar Mirabbasi (University
ofBritishColumbia),LukasChrostowski(UniversityofBritishColumbia),SudipShekhar
(University of British Columbia), Ashkan Seyedi (Nvidia), James Pond (Ansys), Mahdi
Nikdast(ColoradoStateUniversity),AliAsgharEftekhar(AmazonWebServices),Saeed
Fathololoumi (Intel), and Chenyang Wu (Intel).
I am very thankful for the support of Cadence Design System experts and business
leaders in this process. In particular, Gilles Lamant, who read and provided very helpful
suggestions as well as coordinated and supported the feasibility of publishing the book.
Although this effort has been driven by my passion and responsibility to contribute
to the integrated photonics ecosystem, I am sincerely thankful to Intel’s manage-
ment/leadership for recognizing this need and supporting me. Among them are Sreevatsa
Sreekantham, Yuliya Akulova, Todd Swanson, and Hong Hou.
The timely production of the book was made possible by the hard work of the staff at
Springer. I also thank them for their patience during this process.
xi
Disclaimer
Thecodeexamplesprovidedinthisbookarejustforeducationalpurposesandneedproper
modification before being used in production. Any CurvyCore APIs, SKILL/SKILL++
functions and constructs, database-level APIs, and application-level APIs used in this
book are subject to change without notice by Cadence Design Systems, Inc.
Virtuoso®, SKILL®TM, and CurvyCoreTM are trademarks of Cadence Design Sys-
tems, Inc. Cadence grants permission to print examples in this book written in SKILL
and using licensed and copyrighted Cadence APIs. Cadence disclaims all warranties and
Cadence reserves the right to make changes at any time to the published APIs.
xiii
