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Numerical Aperture of Optical Fiber
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## Controls

Start button: To start the experiment.
Switch on: To switch on the Laser.

Select Fiber: To select the type of fiber used.

Select Laser: To select a different laser source.

Detector distance (Z): Use the slider to vary the distance between the source and detector. (ie toward the fiber or away from the fiber.

Detector distance(x): Use the slider to change the detector distance i.e towards left or right w.r.t the fiber.

Show Graph: To Displays the graph.

Reset: To resets the experimental arrangement.

• Drag and drop each apparatus in to the optical table as shown in the figure below. Fig (4)

• Then Click “Start” button.
• Switch On (now you can see a spot in the middle of the detector)
• After that select the Fiber and Laser for performing the experiment from the control options.

## To perform the experiment

• Set the detector distance Z (say 4mm). We referred the distance as “d” in our calculation.
• Vary the detector distance X by an order of 0.5mm, using the screw gauge (use up and down arrow on the screw gauge to rotate it).
• Measure the detector reading from output unit and tabulate it.
• Plot the graph between X in x-axis and output reading in y-axis. See figure 5.
• Find the radius of the spot r, which is corresponding to Imax/2.71 (See the figure 5). Fig (5)

• Then find the numerical aperture of the optic fiber using the equation (4).

### Observation column

 SL No. Screw gauge reading Distance (X) mm I µA H.S.R P.S.R

## Calculations

Distance between the fiber and the detector, d = …………………………… m

Radius of the spot, r =……………………….. m

Numerical Aperture of the optic fiber,  sin(θ) = = ..................

Acceptance angle, θ=  = ...........................

## Result

Numerical aperture of the optic fiber is = …………………
Angle of acceptance = ……………….

Cite this Simulator:

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