HO-ED-F-03 Optical Fiber Characterization Apparatus Breadboard Based
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Optical Fiber Characterization Apparatus
Breadboard Based
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:
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 |
Drawings:
Related Topics:
| Total internal reflection |
| Splice loss |
| Numerical aperture of fiber |
| Single mode and Multi mode fiber |
Scope of Delivery:
Instruction Manual