However, the model still awaits convincing evidence. The unstable disk model is one of several alternative models suggesting that a massive and gravitationally unstable protoplanetary disk could fragment into dense clumps, directly giving birth to wide-orbiting planets. But that process works only when planets form relatively close to their host stars-the gas giants found on wide orbits would not have had time to grow a sufficiently massive core before the gaseous disk dissipated. Rocky planetary cores fed on pebbles or planetesimals, and once the cores reached a certain mass, they began gobbling up the surrounding gas, rapidly becoming giant planets. Scientists converged on the scenario that our solar system’s giant planets formed via accretion within the gaseous protoplanetary disk. In particular, Jupiter-class gas giants on far-flung orbits have challenged what is known as the standard formation scenario. Discoveries of unusual planetary systems don’t make this formidable task any easier. Also, it is the EIA reference test method for both multimode and single mode fibers.Planetary scientists strive to understand the ins and outs of planet formation. The _ method is the most commonly used method for the determination of the fiber refractive index profile.Įxplanation: It is the most commonly used technique. Moreover, it provides the relative refractive index directly without recourse to external calibration.ĩ. It has the advantage that it does not require a leaky mode correction factor. _ method does not require a leaky mode correction factor or equal mode excitation.Įxplanation: Refracted near-field method is complementary to the transmitted near-field method. These effects incarcerate certain changes in the fiber efficiency.Ĩ. They are macro-bending and micro-bending. How many bend effects are produced in the fiber?Įxplanation: Usually, two bend effects are produced.
This is usually because of the bend effects.ħ. The effective cutoff wavelength for a cabled single mode fiber will be generally smaller than that of the un-cabled fiber.Įxplanation: The effective cutoff wavelength for a cabled single mode fiber is always smaller than that of the un-cabled fiber. It shows that in some methods, the values through round robin test are the same.Ħ. What is the name of the test used to determine the efficient values of the effective cutoff wavelength?Įxplanation: Round robin test is an effective method to determine the efficient values for the cutoff wavelength. These are bending-reference technique, power step method and alternative test method.ĥ. How many methods are used to determine the effective cutoff wavelength?Įxplanation: Three methods are usually used for the determination of the effective cutoff wavelength. It is usually called a effective cut-off wavelength.Ĥ. 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 0.1dB.Įxplanation: The cut off wavelength is usually measured by increasing the signal wavelength in a fixed length of fiber until the mode is undetectable. What does ‘a’ stands for in the given equation? M g=(πa/λ) 2(n 1 2 - n 2 2)Įxplanation: The above equation gives the number of guided modes for a parabolic refractive index graded fiber, where a is the core radius and n1, n2 are the core and cladding indices respectively.ģ. It is because the number of bound propagating modes is usually large.Ģ.
A multimode fiber has many cutoff wavelengths.Įxplanation: A multimode fiber has many cutoff wavelengths.
Optical Communications Multiple Choice Questions on “Fiber Cutoff Wavelength Measurements”.ġ.
0 kommentar(er)
