Q. For a GaAs LED, the coupling efficiency is 0.05. Compute the optical loss in decibels.

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Q. In a GaAs LED, compute the loss relative to internally generated optical power in the fiber when there is small air gap between LED and fiber core. (Fiber coupled = 5.5 * 10⁻⁴ Pint)

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Q. Determine coupling efficiency into the fiber when GaAs LED is in close proximity to fiber core having numerical aperture of 0.3.

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Q. If a particular optical power is coupled from an incoherent LED into a low-NA fiber, the device must exhibit very high radiance.

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Q. The amount of radiance in planer type of LED structures is ____________

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Q. In optical fiber communication _____________ major types of LED structures are used.

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Q. As compared to planar LED structure, Dome LEDs have ______________ External power efficiency ___________ effective emission area and _____________ radiance.

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Q. The techniques by Burros and Dawson in reference to homo structure device is to use an etched well in GaAs structure.

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Q. In surface emitter LEDs, more advantage can be obtained by using ____________

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Q. Internal absorption in DH surface emitter Burros type LEDs is ____________

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Q. DH surface emitter generally give ____________

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Q. A DH surface emitter LED has an emission area diameter of 60 μm. Determine emission area of source.

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Q. Estimate optical power coupled into fiber of DH SLED having emission area of 1.96*10⁻⁵, radiance of 40 W/rcm², numerical aperture of 0.2 and Fresnel reflection coefficient of 0.03 at index matched fiber surface.

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Q. In a multimode fiber, much of light coupled in the fiber from an LED is ____________

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Q. Determine the overall power conversion efficiency of lens coupled SLED having forward current of 20 mA and forward voltage of 2 V with 170 μW of optical power launched into multimode step index fiber.

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Q. The overall power conversion efficiency of electrical lens coupled LED is 0.8% and power applied 0.0375 V. Determine optical power launched into fiber.

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Q. Mesa structured SLEDs are used ____________

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Q. The InGaAsP is emitting LEDs are realized in terms of restricted are ____________

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Q. The active layer of E-LED is heavily doped with ____________

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Q. Intrinsically _________________ are a very linear device.

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