Question 1

____________________ lasers are presently the major laser source for optical fiber communications

Accepted Answer

C

Question 2

In Nd: YAG lasers, the maximum doping levels of neodymium is ____________

Accepted Answer

B

Question 3

Which of the following is not a property of Nd: YAG laser that enables its use as an optical fiber communication source?

Accepted Answer

Nd:YAG lasers are known for their single mode operation, narrow line-width, and long lifetime, which are beneficial for optical fiber communication. However, they are not related to semiconductors and integrated circuits in the context of their properties as a communication source.

Question 4

The Nd: YAG laser has a narrow line-width which is ________________

Accepted Answer

The Nd: YAG laser typically has a narrow line-width of less than 0.01 nm, making it suitable for precise applications.

Question 5

The strongest pumping bands is a four level system of Nd: YAG laser at wavelength of range_________________

Accepted Answer

The strongest pumping bands in a four-level system of Nd: YAG laser are in the wavelength range of 0.75 and 0.81 nm. This range is optimal for the absorption of pump light, leading to efficient laser operation.

Question 6

The Nd: YAG laser is costlier than earth-doped glass fiber laser. State whether the following statement is true or false

Accepted Answer

Nd:YAG lasers tend to be more expensive due to their complex solid-state design and the high cost of neodymium doping, compared to the relatively simpler and less expensive production of earth-doped glass fiber lasers.

Question 7

It is a resonant cavity formed by two parallel reflecting mirrors separated by a mirror separated by a medium such as air or gas

Accepted Answer

A Fabry-Perot resonator is a type of optical cavity formed by two parallel reflecting mirrors separated by a medium such as air or gas, used to produce interference patterns.

Question 8

In a three level system, the threshold power decreases inversely with the length of the fiber gain medium.

Accepted Answer

In a three-level system, the threshold power actually increases with the length of the fiber gain medium because longer fibers require more pump power to achieve the population inversion necessary for lasing.

Question 9

Which of the following co-dopant is not employed by neodymium and erbium doped silica fiber lasers?

Accepted Answer

Nitrogen is not typically used as a co-dopant in neodymium and erbium doped silica fiber lasers. The common co-dopants are phosphorus pentoxide, germania, and alumina, which help in modifying the core refractive index, improving the solubility of the rare-earth ions, and altering the laser properties. Nitrogen doping is less common and not standard for these types of fiber lasers.

Question 10

Dopants levels in glass fiber lasers are generally ___________

Accepted Answer

Dopants levels in glass fiber lasers are generally low because high levels can lead to increased absorption and scattering, reducing the efficiency of the laser.

Question 11

. _______________ fibers include addition of lead fluoride to the core glass in order to raise the relative refractive index.

Accepted Answer

ZBLANP fibers include the addition of lead fluoride to the core glass to raise the relative refractive index. This material is a type of heavy metal fluoride glass used in fiber optics for its unique transmission capabilities.

Question 12

The lasing output of the basic Fabry-perot cavity fiber is restricted to between ____________

Accepted Answer

The answer of The lasing output of the basic Fabry-perot...

Question 13

In Fabry-perot laser, the lower threshold is obtained by

Accepted Answer

The answer of In Fabry-perot laser, the lower threshold is...

Question 14

When did the non-semiconductor laser developed?

Accepted Answer

The first non-semiconductor laser, specifically a gas laser (helium-neon laser), was developed in 1960, not 1985. However, none of the provided options correctly matches the historical development of non-semiconductor lasers. The correct year for the development of the first laser (a ruby laser, which is also not a semiconductor laser) is 1960, which is not listed among the options. Therefore, the question seems to contain a factual error regarding the dates and the development of non-semiconductor lasers.

Question 15

Y3Al5 O12 Is a molecular formula for _____________

Accepted Answer

Y3Al5O12 is the molecular formula for yttrium-aluminum garnet, commonly abbreviated as YAG, which is used in various types of solid-state lasers and other optical materials.

Question 16

A perfect semiconductor crystal containing no impurities or lattice defects is called as

Accepted Answer

Intrinsic semiconductors are pure forms of semiconductor materials without any significant impurities or lattice defects. They exhibit semiconductor properties inherently due to their crystal structure and the characteristics of their valence electrons, unlike extrinsic semiconductors which have been intentionally doped with impurities to modify their electrical properties.

Question 17

The energy-level occupation for a semiconductor in thermal equilibrium is described by the

Accepted Answer

The Fermi-Dirac distribution function describes the energy-level occupation for a semiconductor in thermal equilibrium, accounting for the quantum mechanical effects and the Pauli exclusion principle relevant to electrons in a semiconductor.

Question 18

What is done to create an extrinsic semiconductor?

Accepted Answer

Doping the material with impurities introduces additional charge carriers, making it an extrinsic semiconductor. This process alters the electrical properties of the semiconductor by adding donor or acceptor atoms.

Question 19

_________________ is used when the optical emission results from the application of electric field.

Accepted Answer

Electro-luminescence is the phenomenon where light is emitted from a material when an electric field is applied.

Question 20

In the given equation, what does p stands for?

Accepted Answer

In the context of equations related to solid-state physics or semiconductor physics, "p" often stands for crystal momentum.

Quiz 12: Yag Laser and Optical Fiber Communications