Pres2-transmitting of waves by optical.ppt

Introduction to optical communication systems electromagnitics wave, signal transmissions, optical fiber step index greaded index
Introduction to optical communication systems electromagnitics wave, signal transmissions, optical fiber step index greaded index

1. Fundamentals of
Electromagnetic Waves
Xavier Fernando
Ryerson University

2. The Nature of Light
•Quantum Theory–Light consists of
small particles (photons)
•Wave Theory–Light travels as a
transverseelectromagnetic wave
•Ray Theory–Light travels along a
straight line and obeys laws of
geometrical optics. Ray theory is valid
when the objects are much larger than
the wavelength

3. Quantum and Wave Theories

4. Wavelength Ranges

5. Basics about Plane Waves

6. Phase Velocity
v
p

7. Group of Waves

8. Carrier and Envelope
v
p v
g

9. Group Velocity
v
g

10. Field distributions in plane E&M waves
Electric and magnetic
fields are orthogonal
to each other and to
the direction of
propagation Z

11. Polarization states
•If the electric field is oscillating along a
straight line, it is called a linearly
polarized(LP) or plane polarizedwave
•If the E field rotates in a circle (constant
magnitude) or in an ellipse then it is
called a circular or elliptically polarized
wave
•Natural light has random polarization

12. Polarization

13. Adding two linearly polarized waves with a
phase shift will produce an elliptically
polarized light

14. Elliptical Polarization

15. Adding two linearly
polarized waves with zero
phase shift will generate
another linearly polarized
wave

16. Linear Polarization

17. Adding two linearly
polarized waves with
equal amplitude and
90
o
phase shift results
in circular polarized
wave

18. Circular Polarization