Optical fiber connectors Fiber alignment Joint Losses Fiber Splices Fiber connectors Friday,...

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


Coupling Efficiency

s

F

P

P

sourse thefrom emittedpower

fiber theinto coupledpower [5-1]

Source Optical Fiber

sPFP


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)]


Surface emitting LEDs have a Lambertian pattern:

cos),( 0BB [5-2]


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]


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


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]


Examples of possible lensing schemes used to improve optical source-to-fiber coupling efficiency


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.


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]


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


Fiber end face

Fiber end defects


Fiber splicing

Fusion Splicing


V-groove optical fiber splicing


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


Connector Return Loss


Figure 7.8 BNC connectors


Figure 7.5 UTP connector


Figure 7.10 Fiber optics: Bending of light ray


Figure 7.11 Optical fiber


Figure 7.15 Fiber-optic cable connectors


Date post:	17-Jan-2016
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Optical fiber connectors Fiber alignment Joint Losses Fiber Splices Fiber connectors Friday,...

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