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Optical fiber connectorsFiber alignment
Joint Losses Fiber Splices
Fiber connectors
Friday, April 21, 2023 Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/OCN/CONNECTORS
Content
• Launching optical power into a fiber
• Fiber-to-Fiber coupling
• Fiber Splicing and connectors
Friday, April 21, 2023 Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/OCN/CONNECTORS
Coupling Efficiency
s
F
P
P
sourse thefrom emittedpower
fiber theinto coupledpower [5-1]
Source Optical Fiber
sPFP
Friday, April 21, 2023 Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/OCN/CONNECTORS
Radiance (Brightness) of the source
• B= Optical power radiated from a unit area of the source into a unit solid angle [watts/(square centimeter per stradian)]
Friday, April 21, 2023 Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/OCN/CONNECTORS
Surface emitting LEDs have a Lambertian pattern:
cos),( 0BB [5-2]
Friday, April 21, 2023 Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/OCN/CONNECTORS
Fiber-to-Fiber Joint
• Fiber-to-Fiber coupling loss:
• Low loss fiber-fiber joints are either:
1- Splice (permanent bond)
2- Connector (demountable connection)
FFL log10]dB[ [5-8]
Friday, April 21, 2023 Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/OCN/CONNECTORS
Power Coupled from source to the fiber
rdrdddB
dAdABP
s
r
s
A
sssF
m
f f
max0
0
2
0
2
00
sin),(
),([5-4]
source theof angleemission solid and area : and ssA
fiber of angle acceptance solid
and area : and ffA
Friday, April 21, 2023 Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/OCN/CONNECTORS
Power coupled from LED to the Fiber
rdrdB
rdrdB
rdrddBP
s
r
s
r
s
r
s
s
s
22
00
0
2
0
max02
0
0
2
0 0
0
0
NA
sin
sincos2max0
210
2220
22stepLED, 2)NA( nBrBrP ss [5-5]
Friday, April 21, 2023 Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/OCN/CONNECTORS
Examples of possible lensing schemes used to improve optical source-to-fiber coupling efficiency
Friday, April 21, 2023 Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/OCN/CONNECTORS
Different modal distribution of the optical beam emerging from a fiber lead to different degrees of coupling loss. a) when all modes are equally excited, the output beam fills the entire output NA. b)
for a steady state modal distribution, only the equilibrium NA is filled by the output beam.
Friday, April 21, 2023 Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/OCN/CONNECTORS
Mechanical misalignment losses
Lateral (axial) misalignment loss is a dominant Mechanical loss.
2/12
2step, 21
2arccos
2
a
d
a
d
a
d
a
AcommF
[5-9]
Friday, April 21, 2023 Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/OCN/CONNECTORS
Longitudinal offset effect
Losses due to differences in the geometry and waveguide characteristics of the fibers
ERE
RF
ERE
RF
aL
aaa
aaL
NANAfor )NA
NAlog(20)(
for )log(10)(
[5-10]
E & R subscripts refer to emitting and receiving fibers.Friday, April 21, 2023 Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/OCN/CONNECTORS
Experimental comparison of Loss as a function of mechanical misalignment
Friday, April 21, 2023 Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/OCN/CONNECTORS
Fiber end face
Fiber end defects
Friday, April 21, 2023 Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/OCN/CONNECTORS
Fiber splicing
Fusion Splicing
Friday, April 21, 2023 Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/OCN/CONNECTORS
V-groove optical fiber splicing
Friday, April 21, 2023 Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/OCN/CONNECTORS
Optical Fiber Connectors
• Some of the principal requirements of a good connector design are as follows:
1- low coupling losses
2- Interchangeability
3- Ease of assembly
4- Low environmental sensitivity
5- Low-cost and reliable construction
6- Ease of connection
Friday, April 21, 2023 Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/OCN/CONNECTORS
Connector Return Loss
Friday, April 21, 2023 Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/OCN/CONNECTORS
Figure 7.8 BNC connectors
Friday, April 21, 2023 Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/OCN/CONNECTORS
Figure 7.5 UTP connector
Friday, April 21, 2023 Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/OCN/CONNECTORS
Figure 7.10 Fiber optics: Bending of light ray
Friday, April 21, 2023 Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/OCN/CONNECTORS
Figure 7.11 Optical fiber
Friday, April 21, 2023 Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/OCN/CONNECTORS
Figure 7.15 Fiber-optic cable connectors
Friday, April 21, 2023 Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/OCN/CONNECTORS