# Physics of linear and nonlinear optical waveguides

By Prof. Samudra Roy   |   IIT Kharagpur
Learners enrolled: 330
Optical waveguide is a physical structure that guides electromagnetic waves and it is the most important component of integrated optical circuits. This course is intended to describe the theoretical basis of optical waveguides. In this course we learn the principal of light guidance by understanding the light-matter interaction in linear and nonlinear regime. We will also discuss different optical components based on waveguides that are used extensively in communication and sensing. This course is mostly self-contained with very basic prerequisites like knowledge of elementary algebra and calculus. The course is prepared for the senior graduate and M.Sc. students having a prior knowledge of electromagnetic theory. The course is also useful to the junior PhD students and M-Tech students whose research interest is related to Photonics. The exam of this course will be based on multiple choice questions and each week the descriptive type practice-assignments will be given to the students as home work.

INTENDED AUDIENCE : 3rd year B. Sc Physics , M. Sc Physics , M-Tech (Applied
PREREQUISITES : Basic calculus, Algebra, Basic complex numbers, Basic concept of electrodynamics
INDUSTRIES SUPPORT : None
Summary
 Course Status : Completed Course Type : Elective Duration : 12 weeks Category : Physics Credit Points : 3 Level : Undergraduate/Postgraduate Start Date : 24 Jan 2022 End Date : 15 Apr 2022 Enrollment Ends : 07 Feb 2022 Exam Date : 23 Apr 2022 IST

Note: This exam date is subjected to change based on seat availability. You can check final exam date on your hall ticket.

### Course layout

Week 1:Linear and nonlinear optical waveguides & Brief history, Maxwell’s equation, Plane wave, Wave equation, Snell’s Law, Total Internal Reflection, Concept of core and cladding
Week 2:Numerical Aperture (NA), V-parameter, Cut off wavelength, Ray propagation in optical fibers, Meridonial rays, Skew ray, Concept of discrete ray propagation inside waveguides
Week 3: Waveguide characteristics: Loss mechanism, Modal dispersion, Ray Equation, Ray path for step-index waveguide
Week 4:Ray equation continue: Ray path for triangular-index waveguide, Ray path for parabolic index waveguide, Transit Time
Week 5:Material Dispersion, Group delay, Pulse broadening, Concept of zero dispersion, Birefringence waveguides
Week 6:Modes: TE & TM Modes, Modes in slab waveguide, Symmetric and anti-symmetric mode, Calculation of propagation constant
Week 7: Modes: Step index optical fibers, Bassel function, Recursion relation, LPlm modes
Week 8:Optical waveguide components: Directional coupler, Optical switching, Power coupler, Wavelength Division Multiplexing (WDM), Couple Mode Theory
Week 9:Fiber Bragg Grating (FBG), Bragg wavelength, Reflectivity calculation, Linear waveguide array
Week 10:Nonlinear Waveguides, Kerr nonlinearity, EM wave propagation under Kerr nonlinearity
Week 11: Nonlinear Susceptibility, Second Harmonic Generation (SHG), Third Harmonic Generation (THG), Phase Matching
Week 12:Self Phase Modulation (SPM), Nonlinear absorption, Optical Soliton, Supercontinuum Generation

### Books and references

1. Fundamental of optical waveguides by K. Okamoto
2. Optical waveguide theory by A. Snyder & J. Love
3. Waveguide nonlinear-optic device by T. Suhara & M. Fujimura
4. Photonics by A. Yariv & P. Yeh
5. Introduction to fiber optics by A. Ghatak & K. Thyagarajan

### Prof. Samudra Roy

IIT Kharagpur
I did my PhD from CGCRI (a CSIR Lab) in 2009 and carried out my post-doctoral research from Hokkaido University, Japan and Max Planck Institute, Germany during 2009-2013. In 2013, I joined in the Physics Department, IIT-Kharagpur as an assistant professor and also associated with the Center for Theoretical Studies-IIT Kharagpur. My research field is nonlinear photonics.

### Course certificate

The course is free to enroll and learn from. But if you want a certificate, you have to register and write the proctored exam conducted by us in person at any of the designated exam centres.
The exam is optional for a fee of Rs 1000/- (Rupees one thousand only).
Date and Time of Exams: 23 April 2022 Morning session 9am to 12 noon; Afternoon Session 2pm to 5pm.
Registration url: Announcements will be made when the registration form is open for registrations.
The online registration form has to be filled and the certification exam fee needs to be paid. More details will be made available when the exam registration form is published. If there are any changes, it will be mentioned then.
Please check the form for more details on the cities where the exams will be held, the conditions you agree to when you fill the form etc.

CRITERIA TO GET A CERTIFICATE

Average assignment score = 25% of average of best 8 assignments out of the total 12 assignments given in the course.
Exam score = 75% of the proctored certification exam score out of 100

Final score = Average assignment score + Exam score

YOU WILL BE ELIGIBLE FOR A CERTIFICATE ONLY IF AVERAGE ASSIGNMENT SCORE >=10/25 AND EXAM SCORE >= 30/75. If one of the 2 criteria is not met, you will not get the certificate even if the Final score >= 40/100.

Certificate will have your name, photograph and the score in the final exam with the breakup.It will have the logos of NPTEL and IIT Kharagpur .It will be e-verifiable at nptel.ac.in/noc.

Only the e-certificate will be made available. Hard copies will not be dispatched.

Once again, thanks for your interest in our online courses and certification. Happy learning.

- NPTEL team