1. Page 1FO-DIV/GLFO_BASICS_1c.PPT
Principles of Transmission

2. Page 2FO-DIV/GLFO_BASICS_1c.PPT
Fiber Optic General Basics Part I
Fiber Optic Transmission
Fiber Optic Systems
Principle of Lightwave Propagation
Fiber Parameters
Guide through Optical Components
Measurement Parameters and
Applications

3. Page 3FO-DIV/GLFO_BASICS_1c.PPT
Principal F.O. Transmission
 the electrical signal processing is according to international
standards
 the convertion into the "optical freuqency band" enables to use
the advantages coming up with F.O. transmission
electrical
signal
processing
Electrical
Transmission
E / O -
Conversion
Electrical
Transmission
O / E -
Conversion
electrical
signal
processing
Optical
Transmission
Fiber as transmission medium

4. Page 4FO-DIV/GLFO_BASICS_1c.PPT
Application area of fiber optics technology
 Telecom long distance, FITL
 Datacom LAN, MAN / WAN
 Industry remote control of machines

5. Page 5FO-DIV/GLFO_BASICS_1c.PPT
Fiber Optic General Basics Part I
Fiber Optic Transmission
Fiber Optic Systems
Principle of Lightwave Propagation
Fiber Parameters
Guide through Optical Components
Measurement Parameters and
Applications

6. Page 6FO-DIV/GLFO_BASICS_1c.PPT
Direct Modulation
 Systems are operated by direct drive current modulation of the
transmitter according to the electrical signal !
 LASERS have to be operated above the Ith (threshold current) !
REMIND LASER SAFETY REGULATIONS !
Popt
If
t->
LED
fmod:
up to 250 Mbaud
Popt
IfIth
t->
LASER
fmod:
up to 10 Gbaud

7. Page 7FO-DIV/GLFO_BASICS_1c.PPT
Fiber Optic Basics
Fiber Optic Transmission
Fiber Optic Systems
Principle of Lightwave Propagation
Fiber Parameters
Guide through Optical Components
Measurement Parameters and
Applications
Measurement Instruments

8. Page 8FO-DIV/GLFO_BASICS_1c.PPT
Formula
Phase velocity c c = x f wavelength
f frequency
Phase velocity c0 c0 = 300 000 Km/s
(in vacuum)
Refractiv index ni ni = c0 : ci
ni refractiv index in medium i
c0 velocity in vacuum
ci velocity in medium i
Snell´s law (refraction law)
sin 1 / sin 2 = n2 / n1 = c1 / c2
1 angle of incident in medium 1
2 angle of transition medium 2
n1 refractiv index in medium 1
n2 refractiv index in medium 2
c1 velocity in medium 1
c2 velocity in medium 2
Phase velocity cGl cGl ~ 200 000 Km/s
(in glas)

9. Page 9FO-DIV/GLFO_BASICS_1c.PPT
Fiber Construction
 Independent from the fiber type the rule is:
Core and cladding are building up the "fiber"
core
cladding
coating
n core
n cladding
n core
n cladding
Step-index fiber Graded-index fiber