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Fundamentals of Photonics

or Introduction to Lightwave Technologies (ILT)

This course is offered each Spring semester by the Department of Electrical and Computer Engineering at Aarhus University, as part of its comprehensive Photonics Teaching Program.

Overview

Watch a brief introduction to the course in this 1-minute video: MP4

Purpose, etc.

Purpose of the course

This course provides students with a solid foundation in the principles and applications of photonics. By covering essential topics such as electric and magnetic fields, light propagation, optical fibers, and photodetection, this course prepares electrical engineering students to tackle cutting-edge challenges in telecommunications, medical imaging, and quantum computing. It combines theoretical knowledge with practical lab exercises and offers networking opportunities with industry leaders. This course opens up new avenues for innovation and career opportunities in high-tech industries.

Learning outcome

  1. Master photonic basics: Analyze and explain light propagation, modulation, and detection, demonstrating a deep understanding of these fundamental concepts.
  2. Hands-on experience: Apply and demonstrate proficiency with cutting-edge photonic devices, including optical fibers and photodetectors.
  3. Systems integration: Synthesize knowledge to design and analyze complex photonic systems, enhancing your problem-solving abilities.
  4. Innovative design: Create and develop novel photonic solutions for advanced applications of industrial relevance, demonstrating innovative thinking.
  5. Research skills: Critically evaluate and investigate the latest advancements and challenges in optical technologies, conducting independent research.

Course content

The course covers the fundamental principles and applications of photonics. Key subjects include:

  1. Basics of photonics: Explore the basics of electric and magnetic fields, and the propagation of light.
  2. Core optical components: Study of the working principles of lasers, waveguides, and photodetectors.
  3. Light modulation: Learn advanced techniques for modulating light for various applications.
  4. Integrated photonics systems: Design and analysis of photonic circuits and systems.
  5. Real-world applications: Discover how photonics revolutionizes telecommunications, medical imaging, and quantum computing.
  6. Hands-on lab work: Gain practical experience with state-of-the-art photonic devices and systems.

ECTS credits: 5

Course coordinator: Nick Volet

Program requirement: Active participation is mandatory.

Prerequisites: Prior knowledge of electromagnetism and optics.

Course assessmentEvaluation will be based on an oral exam, centered on a design study you will develop, incorporating one or more research papers related to lightwave technologies. Grading will follow the seven-point scale and will include an external co-examiner.

Where and when?

  • At AU-ECE, Building 5125 ("Edison", Finlandsgade 22)
    Lectures: 
    – Mondays 12:00–14:00 in Room 120
    Exercises + lab demos: 
    – Thursdays 10:00–12:00 in Room 423

Part 1

1. Electric and magnetic fields

Jan. 27 + 30 (week 5)
Recap on complex numbers and differential operators.
Maxwell's equations and complex fields.
Fourier decomposition, separation of variables and trial solution.
Pulses, small-signal modulation and continuous-wave (cw) operation.
Wavenumber, attenuation coefficient and effective refractive index. 
Expressions for the electric field.

  • Solutions: PDF

→ Start survey: We’re excited to begin this semester with you! To help us better tailor the course to your needs and interests, we’d love to hear your expectations and any suggestions you may have. Your feedback is valuable, and the survey is completely anonymous. Please share your thoughts by clicking this link.


2A. Direction of propagation

Feb. 3 + 6 (week 6)
Constitutive relations, Helmholtz equation, wave propagation, optical losses, and nonlinear effects.

  • Solutions: PDF

2B. Direction of propagation

Feb. 10 + 13 (week 7)
Relative directions of the fields.
Poynting vector, time average.
Intensity and optical power.
Wave types: plane, Gaussian, and guided modes.
Material anisotropy and the walk-off effect.
Nonlinear optics: second- and third-order effects.

During the exercice session on Thursday, we will use the software EMode Photonix.
Information on how to get started can be found here.
Please go through the information provided at this link and install the license.

  • Solutions: PDF

3. Interface between materials

Feb. 17 + 20 (week 8)
Boundary conditions. Snell's law.
Total internal reflection and evanescent field.
Transverse polarizations: TE and TM waves.
Reflection and transmission coefficients.
Fresnel’s equations and Brewster’s angle.
Phase shifts upon reflection.
Thin films: antireflection (AR) coating, bandpass filter, distributed Bragg reflector (DBR).
Goos-Hänchen effect.


4. Gaussian waves

Feb. 24 + 27 (week 9)
Dispersion relation and paraxial wave equation. Material refractive index.
Gaussian beam solution: beam waist, Rayleigh range, divergence.
Gouy phase shift and wavefront curvature.
Effective beam area, M-squared parameter.


5. Generation of light

March 3 + 6 (week 10)
Incandescence and blackbody radiation.
Planck's spectrum, Wien's law.
Quantum mechanics foundations.
Spontaneous and stimulated emission.
Optical amplification and lasers.

→ Friday, week 10: Deadline to submit group abstracts

  • Booklet: TBC
  • Slides: PDFPPT
  • Exercises: PDF

Internship and Project Day: March 7 (Friday, week 10)
Starting at 7:45 in Building 5122, Room 122.
See this LinkedIn post.


6A. LED and laser characteristics

March 10 + 13 (week 11)
Power/voltage vs current, optical spectrum.
Multi-mode vs single-mode.

 Monday, week 11: Feedback on submitted abstracts: PDF

  • Booklet: TBC
  • Slides: PDFPPT
  • Exercises: PDF

Introduction to Integrated Nonlinear Photonics 
March 11 (week 11)


6B. Wavelength conversion

March 17 + 20 (week 12)
Second-harmonic generation.
Optical frequency combs.

  • Booklet: TBC
  • Slides: PDFPPT
  • Exercises: PDF - EMode Script - PY

7. Optical spectrum

March 24 + 27 (week 13)
Ensemble average. Wiener-Khintchine theorem.
Phase noise, frequency noise and intrinsic linewidth.
Lorentzian spectrum of an ideal laser.
Flicker noise and dither tones.

November 2024: Guest lecture from Asger Sellerup Jensen, Senior Market Development Manager & Head of Quantum at NKT Photonics
Video: MPG


Research Day: March 26 (Wednesday, week 13)
Pitches starting at 12:30 in Peter Bøgh Andersen Auditory in Building 5335.
Poster session starting at 13:30 in Building 5122, Room 122.


(8). Polarization of light

Polarization ellipse. State of polarization.
Stokes parameters.
Polarizers and waveplates.
Müller matrices.

  • Booklet: PDF
  • Slides: PDFPPT
  • Exercises: Lab session

Part 2

(9). Modes in optical fibers (part 1)

Dispersion relation.
Characteristic equation and effective index.
Single-mode condition.


(10). Modes in optical fibers (part 2)

Intensity distribution.
Hybrid modes.
Electric mode profiles.


11. Multiplexing

March 31 + April 3 (week 14)
Wavelength division multiplexing (WDM).
Splitters and combiners.

April 3 (Thursday, week 14): Group presentations
April 4 (Friday, week 14): Deadline to submit individual abstracts

  • Booklet: TBC
  • Slides: PDFPPT
  • Exercises: PDF

Introduction to Photodetection (April 3, week 14)


12. Directional couplers and interferometers

April 7 + 10 (week 15)
Directional couplers and supermodes. Phase-matching condition.
Mach-Zehnder interferometers (MZIs).
Multi-mode interference (MMI) couplers.
Optical hybrids and coherent receivers.

 Monday, week 15: Feedback on submitted abstracts: PDFPPT


→ April 14 – 20 (week 16): No teaching at AU (Easter week)

→ April 21 (Monday, week 17): No teaching (Easter Monday)


National Optics Congress at DTU: April 23 + 24 (week 17)
Great opportunity to network with #photonics stakeholders.
For students: all expenses paid for the conference experience including transport and accommodation.


12. Ring resonators

April 28 + May 1 (week 18)
Transmission spectrum. Critical coupling.
Quality factor. Effective phase shift.
Applications: filters, mirrors, isolators, optical frequency combs, and all-optical switches.


13. Phase modulation

May 5 + 8 (week 19)
Electro-optic effects. Pockels cells.
Electro-optic modulators (EOMs). Generation of sidebands.

  • Booklet: PDF
  • Slides: PDF – PPT
  • Exercises: TBC

14. Last session

May 12 + 15 (week 20)
Recap.
→ Course evaluation

May 15 (Thursday, week 20): Individual presentations (rehearsal)

Simulation exercises

For the numerical simulation of waveguide modes, we will be using EMode Photonix software. This tool is essential for accurately modeling and analyzing waveguide behavior.
Detailed instructions and resources to help you begin using EMode Photonix can be found here.


Exam: June 19 (Thursday, week 25)

Evaluation will be based on an oral exam, centered on a design study you will develop, incorporating one or more research papers related to lightwave technologies.

  • April 4 (Friday, week 14): Deadline to submit your abstract
  • May 15 (Thursday, week 20): Individual presentations (rehearsal)

For those that would like to attend the exam, please send your abstract to Nick Volet by email before the above deadline.

The exam is oral, and the duration is 20 min.
We ask you to prepare a presentation for 10 min, leaving 10 min for questions.



Storage

LaTeX files (for booklets and exercises) are available at this Overleaf project.

Slides and other files are available at this SharePoint site.