1. Opto Electronics ( ET – 421) FALL-213 Lecture# 01 Introduction “optical communication” Engr. Tasleem Kausar

2. Text Books Gerd Keiser, “Optical Fiber Communications”, McGraw–Hill, 3/e G. P. Agrawal, “Fiber-Optic Communication Systems” Wiley, 3/e Richard S. Quimby,“Photonics and Lasers An Introduction”

3. Grading Policy Assignments, Quizzes, Attendance, Computer Simulations(10%) Course Project(10%) Mid Semester Exams(20%) End Semester Exams(60%)

4. Miscellaneous ► Web Page: Course management system(CMS) ► Office Hours : Monday (1:00 PM - 3:30 PM) ► Contact: tasleem.kausar@uettaxila.edu.pk

5. Communication??? Channel/medium i.e guided or un-guided Signal get distortion

6. Why Optical Communications In eight century B.C Greeks use fire to communicate Electrical Systems, signals are supper imposed onto the carrier(Electromagnetic waves) Problem ??? Data rate Distance

7. Electromagnetic Spectrum

9. Wavelength Bands of Interest 50 nm (UV) – 100 μ m (IR) 400 nm – 700 nm (visible region) 800 nm – 1600 nm (1.55μm) range

10. Choice of wavelength

11. First Window(820nm-880nm) Second Window(1200nm-1320) Third Window(1550nm-1610nm)

12. Optical Communications Benefits Extremely wide bandwidth: High carrier frequency ( a wavelength of 1552.5 nm corresponds to a center frequency of 193.1 THz) Small size & light weight Immunity to Interference: Electromagnetic interference (high voltage transmission lines, radar systems, power electronic systems, airborne systems,...) Signal Security

13. Optical Communications Benefits Lack of EMI cross talk between channels Ruggedness and Flexibility Low Transmission loss (0.25 to 0.3 dB/km) System Reliability and Ease of Maintenance: high performance active & passive photonic components such as tunable lasers, very sensitive photo detectors, couplers, filters, Low Cost systems for data rates in excess of Gbps

14. Practice question 01 How carrier frequency relate with data rate and transmission range/distance

15. Practice question 02 Why there is a difference between uplink and down link frequency range?