Optical Fiber Characterization

Apparatus  -

Model: HO-ED-F-03

In the model HO-ED-F-03, components are mounted on an optical breadboard (800 x 600mm) for performing the experiment. The use of optical breadboard makes the system flexible and helps to setup the experiments easily. In this model, various components can be arranged on the breadboard with desired configurations. There are M6 tap holes at 25mm grid throughout the breadboard to facilitate mounting.

The experiment helps students to understand concepts of numerical aperture, bending loss, splice loss, total internal reflection etc. The laser light is coupled to optical fiber by the use of an objective lens for maximum coupling efficiency. Numerical aperture is found out by scanning the far field of the optical fiber using a photo detector mounted on a translation stage.

Experiment Examples

Numerical aperture measurement of multi-mode fiber

The Numerical Aperture is given by,

NA  =  Sin θa

Where θa is the Acceptance angle

Measurement of bending loss in multi-mode fiber

The bend of a fiber causes loss in emittance and increase in attenuation as the angle of incidence decreases at the points where curveted radius is too small and the condition of total internal reflection is not fulfilled. In this experiment an apparatus of varying radii is used to study the bending losses involved. When a fiber is bend specified number of turns on various diameters, loss occurs in accordance with the diameter and it can be seen that, the loss will increase with respect to the decrease in diameter.

Relative measurement of splice loss in multi-mode fiber

Splice loss is caused by a number of factors. Loss is minimized when the two fiber cores are identical and perfectly aligned, splices are properly finished and no dirt is present. Only the light that is coupled into the receiving fiber's core will propagate, so all the rest of the light becomes splice loss

Numerical aperture measurement of single mode fiber

The Numerical Aperture is given by,

NA  =  Sin θa

Where θa is the Acceptance angle

Calculation of normalized frequency or V-number of single mode fiber

In an optical fiber, the normalized frequency, the V number is given by

V  =  (  2πa  /  λ  )  √  (  n1  -  n2  )

V  =  (  2πa  /  λ  )  NA

Where a is the core radius, λ is the wavelength in vacuum, n1 is the maximum refractive index of the core, n2 is the refractive index of the homogeneous cladding, and applying the usual definition of the numerical aperture NA.

Calculation of mode field diameter of single mode fiber.

For a Gaussian power distribution (lasers used in communications have Gaussian power distribution) in a single mode optical fiber, the mode field diameter (MFD) is defined as the point at which the electric and magnetic field strengths are reduced to 1   /   e2 of their maximum values, i.e., the diameter at which power is reduced to 1   /   e2   (0.135) of the peak power (because the power is proportional to the square of the field strength). For single mode fibers, the peak power is at the center of the core.

Determination of refractive index of transparent solids

According to Snell’s law,

V  =  sin i  /  sin r

Where, n is the refractive index of transparent medium, i is the angle at which light enters the medium and r is the angle at which it gets refracted.

Features

Easy and flexible

Experiments based on both single mode and multi-mode fibers

Diode laser is used as light source

High precision laser coupler

Photo transistor type photo detector

Rigid base

Corrosion free components
Related Topics

Total internal reflection

Splice loss

Numerical aperture of fiber

Single mode and Multi mode fiber
Scope of Supply

Model No: ED-F-03-BBS
Dimensions
:
800mm x 600mm
Material
:
Black anodized Aluminum alloy
Quantity
:
1 no.

Kinematic Laser Mount

Model No: ED-F-02-KLM
Material
:
Black anodized Aluminum alloy
:
:
+/-4 degrees
Quantity
:
1 no.

Detector Mount

Model No: ED-F-02-DM
Material
:
Black anodized Aluminum alloy
Diameter
:
30 mm
Quantity
:
1 no.

XYZ Translation stage with Mount

Model No: ED-F-02-XYZT
Material
:
Black anodized Aluminum alloy
Travel
:
Micrometer controlled
Resolution
:
0.01 mm
Quantity
:
1 no.

Laser Fiber Coupler with Mount

Model No: ED-F-02-LFCM
Magnification of objective
:
10 X
Positioning
:
Quantity
:
1 no.

Fiber Holder with Angular Tilt

Model No: ED-F-02-FHAT
Material
:
Black anodized Aluminum alloy
Resolution
:
2 degree
Quantity
:
1 no.

Fiber Chuck Holder

Model No: ED-F-02-FCH
Material
:
Black anodized Aluminum alloy
Quantity
:
1 no.

Bending Loss Apparatus

Model No: ED-F-02-BLA
Chuck material
:
Nylon
Step diameter
:
35, 45, 55, 65 mm
Quantity
:
1 no.

Fiber Chuck

Model No: ED-F-02-FC
Material
:
Black anodized Aluminum alloym
Diameter
:
30 mm
Quantity
:
1 no.

Single Mode Optical Fiber

Model No: ED-F-02-SMOF
Material
:
Glass fiber
Numerical Aperture
:
0.11
Core Dia
:
9 micron
Length
:
3 meters
Quantity
:
1 no.

Multi Mode Optical Fiber

Model No: ED-F-02-MMOF
Material
:
Plastic Fiber
Numerical Aperture
:
0.5
Core Dia
:
735, 240 microns
Length
:
5 meters
Quantity
:
1 no. each.

Diode Laser with Power supply (Red)

Model No: ED-F-02-DLPR
Wave length
:
650 nm
Optical power
:
5 mW
Quantity
:
1 no.

Detector with Output Measurement Unit

Model No: ED-F-02-DOMU
Sensor Type
:
Photo Transistor
Display
:
7 segment, 3 ½ digit
Range
:
0 - 199 milli / micro amperes
Quantity
:
1 no.

Accessories

User Manual

Multi Mode Optical Fiber – 250 – 5 mtr

Model No. ED-F-02-MMOF250
\$ 12.00

Multi Mode Optical Fiber – 750 – 5 mtr

Model No. ED-F-02-MMOF750
\$ 20.00