Q. What does ‘a’ stands for in the given equation?

Mg=(πa/λ)²(n₁² – n₂²)

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Q. The _________ wavelength is defined as the wavelength greater than which the ratio of the total power and the fundamental mode power has to be decreased to less than 0.1 dB.

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Q. How many methods are used to determine the effective cutoff wavelength?

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Q. What is the name of the test used to determine the efficient values of the effective cutoff wavelength?

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Q. The effective cutoff wavelength for a cabled single mode fiber will be generally smaller than that of the un-cabled fiber.

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Q. How many bend effects are produced in the fiber?

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Q. _______________ method does not require a leaky mode correction factor or equal mode excitation.

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Q. The _______ method is the most commonly used method for the determination of the fiber refractive index profile.

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Q. The ____________ affects the light gathering capacity and the normalized frequency of the fiber.

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Q. The numerical aperture for a step index fiber is sine angle of the ____________

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Q. The calculations of the numerical aperture from a refractive index data are less accurate for the graded index fibers than for step index fibers.

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Q. Far field pattern measurements with regard to multimode fibers are dependent on the _____________ of the fiber.

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Q. The screen is positioned 10 cm from the fiber end face. When illuminated from a wide angled visible source the measured output pattern size is 6.2 cm. Calculate the approximate numerical aperture of the fiber.

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Q. During the fiber drawing process, the fiber outer diameter is maintained constant to within ________

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Q. What is the minimum value of accuracy in diameter is needed to avoid radiation losses in the fiber?

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Q. Which of the following is a non-contacting optical method of on-line diameter measurement?

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Q. The shadow method is used for measurement of the outer diameter of an optical fiber. The apparatus employs a rotating mirror with an angular velocity of 4 rad/s which is located at 10 cm from the photo detector. Compute the shadow velocity.

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Q. The shadow velocity is given by 0.4 μm μs⁻¹ and shadow pulse of width 300 μs is registered at an instant by the photodetector. Determine the outer diameter of the optical fiber in μm.

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Q. The techniques used to determine the refractive index profile can also be used to determine the core diameter.

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Q. ____________ affects both the fiber attenuation and dispersion.

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