Question

Dependence of attenuation on the wavelength?

Dependence of LP modes on wavelength?

Answer #1

For electromagnetic radiation, attenuation is generally caused by
the incident radiation. EM waves cause the electron clouds of the
molecules in the medium to oscillate. Other sources may include
scattering due to opaque impurities present. Therefore, all
radiation faces attenuation in a medium.

However, if the frequency(thereby wavelength) of the incident light
matches for the excitation energy of the electron cloud, there is
stronger scaterring due to the process of absorption and emission.
In this way, certain wavelengths are attenauated far more than
their neighbouring wavelengths in a medium.

For Linearly Polarized modes, there is no dependence on wavelength.
However, shorter the wavelength, more the LP modes that can be
guided into a optical fibre.

Consider a wavelength of 550nm travelling through 150km of air.
Assume the number density of molecules to be 2.5 × 10^25 ?-3. Use
this information to determine the following:
a) Calculate the attenuation coefficient
(β);
b) Determine the attenuation length
(1/β);
c) Determine the relative reduction in
intensity of this wavelength;
d) Convert this to percentage reduction in intensity;
and
e) How far must the wave travel to reach 1%
reduction in intensity?

A light source, output power of 80mW, is connected to 50km of
fiber, having an attenuation of 0.23dB/km at the
source wavelength. At EACH end there is a coupling loss of
0.5dB.
(c) Calculate the loss just due to the fiber, in dB and in
mW.
(d) Calculate the total loss of the system, in dB and in mW.
(e) Calculate the output power through the fiber line, in mW.

To apply Problem-Solving Strategy 12.1 Standing waves and normal
modes. A cellist tunes the C string of her instrument to a
fundamental frequency of 65.4 Hz H z . The vibrating portion of the
string is 0.600 m m long and has a mass of 14.4 g g . With what
tension must she stretch that portion of the string? What
percentage increase in tension is needed to increase the frequency
from 65.4 Hz H z to 73.4 Hz H...

Consider a He-Ne laser oscillating at the wavelength of λ =
632.8 nm with a Doppler-broadened gain linewidth of Δνg
= 1.7×109 Hz. (The gain linewidth is the width of the
Gaussian distribution of the gain of the laser medium. For gas
lasers it is usually determined by Doppler broadening.) Assume that
the laser operates with a resonator of length L = 50 cm. Calculate
the number of modes in which the laser can emit laser light.
Hint: calculate the...

The magnetic field in a plane monochromatic electromagnetic wave
with wavelength λ = 684 nm, propagating in a vacuum in the
z-direction is described by
B⃗ =(B1sin(kz−ωt))(i^+j^)B→=(B1sin(kz−ωt))(i^+j^)
where B1 = 5.3 X 10-6 T, and
i-hat and j-hat are the unit vectors in the +x and +y directions,
respectively.
5)
Which of the following equations describes the spatial and time
dependence of the electric field oscillations?
6)
What is tmax, the first time after t = 0, when the
magnitude...

Learning Outcomes (Unit 2)
Perform quantitative calculations based on the relationship
between wavelength, energy, and the speed of light.
Identify and rank the different types of radiation which
comprise the electromagnetic spectrum.
Explain why classical mechanics doesn't describe electromagnetic
radiation.
Describe the photoelectric effect and relate the energy and/or
intensity of the photons to the work function and kinetic energy of
the ejected electrons.
Explain the origin of atomic and emission spectra and relate
these spectra to discrete energy levels....

⦁ A person sitting in a stationary boat notices that
it takes the water waves 2 seconds to pass the entire length of the
boat that is 12 m. Calculate the speed of the water waves. Show
your calculation.
12/2 = 6m/s
⦁ The person in Question #1 also notices the water
waves passing by the bow of the ship once every 4 seconds. b) What
are the frequency and c) the wavelength of the water waves? Show
all your...

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