Explore topic-wise MCQs in Optical Communication.

This section includes 26 Mcqs, each offering curated multiple-choice questions to sharpen your Optical Communication knowledge and support exam preparation. Choose a topic below to get started.

1.

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

A. True
B. False
Answer» B. False
Discussion
2.

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

A. 0.9
B. 0.3
C. 0.6
D. 0.12
Answer» B. 0.3
Discussion
3.

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 * 10-4Pint)

A. 34 dB
B. 32.59 dB
C. 42 dB
D. 33.1 dB
Answer» C. 42 dB
Discussion
4.

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

A. 12.3 dB
B. 14 dB
C. 13.01 dB
D. 14.6 dB
Answer» D. 14.6 dB
Discussion
5.

A planar LED is fabricated from GaAs is having a optical power emitted is 0.018% of optical power generated internally which is 0.018% of optical power generated internally which is 0.6 P. Determine external power efficiency.

A. 0.18%
B. 0.32%
C. 0.65%
D. 0.9%
Answer» E.
Discussion
6.

A planar LED fabricated from GaAs has a refractive index of 2.5. Compute the optical power emitted when transmission factor is 0.68.

A. 3.4 %
B. 1.23 %
C. 2.72 %
D. 3.62 %
Answer» D. 3.62 %
Discussion
7.

The Lambertian intensity distribution __________ the external power efficiency by some percent.

A. Reduces
B. Does not affects
C. Increases
D. Have a negligible effect
Answer» B. Does not affects
Discussion
8.

Compute power internally generated within a double-heterojunction LED if it has internal quantum efficiency of 64.5 % and drive current of 40 mA with a peak emission wavelength of 0.82 μm.

A. 0.09
B. 0.039
C. 0.04
D. 0.06
Answer» C. 0.04
Discussion
9.

In a junction diode, an equilibrium condition occurs when ____________

A. Δngreater than Δp
B. Δnsmaller than Δp
C. Constant current flow
D. Optical amplification through stimulated emission
Answer» D. Optical amplification through stimulated emission
Discussion
10.

The carrier recombination lifetime becomes majority or injected carrier lifetime.

A. True
B. False
Answer» C.
Discussion
11.

The excess density of electrons Δnand holes Δpin an LED is ____________

A. Equal
B. Δpmore than Δn
C. Δn more than Δp
D. Does not affects the LED
Answer» B. Δpmore than Δn
Discussion
12.

THE_LAMBERTIAN_INTENSITY_DISTRIBUTION____________THE_EXTERNAL_POWER_EFFICIENCY_BY_SOME_PERCENT.?$

A. Reduces
B. Does not affects
C. Increases
D. Have a negligible effect
Answer» B. Does not affects
Discussion
13.

A planar LED is fabricated from GaAs is having a optical power emitted is 0.018% of optical power generated internally which is 0.018% of optical power generated internally which is 0.6 P. Determine external power efficiency.$

A. 0.18%
B. 0.32%
C. 0.65%
D. 0.9%
Answer» E.
Discussion
14.

A_planar_LED_fabricated_from_GaAs_has_a_refractive_index_of_2.5._Compute_the_optical_power_emitted_when_transmission_factor_is_0.68.$

A. 3.4 %
B. 1.23 %
C. 2.72 %
D. 3.62 %
Answer» D. 3.62 %
Discussion
15.

If a particular optical power is coupled from an incoherent LED into a low-NA fiber, the device must exhibit very high radiance . State whether the given statement is true or false.

A. True
B. False
Answer» B. False
Discussion
16.

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

A. 0.9
B. 0.3
C. 0.6
D. 0.12
Answer» B. 0.3
Discussion
17.

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 * 10-4Pint)

A. 34 dB
B. 32.59 dB
C. 42 dB
D. 33.1 dB
Answer» C. 42 dB
Discussion
18.

For_a_GaAs_LED,_the_coupling_efficiency_is_0.05._Compute_the_optical_loss_in_decibels.

A. 12.3 dB
B. 14 dB
C. 13.01 dB
D. 14.6 dB
Answer» D. 14.6 dB
Discussion
19.

Compute power internally generated within a double-heterojunction LED if it has internal quantum efficiency of 64.5 % and drive current of 40 mA with a peak emission wavelength of 0.82 μm?#

A. 0.09
B. 0.039
C. 0.04
D. 0.06
Answer» C. 0.04
Discussion
20.

Determine the internal quantum efficiency generated within a device when it has a radiative recombination lifetime of 80 ns and total carrier recombination lifetime of 40 ns.

A. 20 %
B. 80 %
C. 30 %
D. 40 %
Answer» C. 30 %
Discussion
21.

Determine the total carrier recombination lifetime of a double heterojunction LED where the radioactive and nonradioactive recombination lifetime of minority carriers in active region are 70 ns and 100 ns respectively.

A. 41.17 ns
B. 35 ns
C. 40 ns
D. 37.5 ns
Answer» B. 35 ns
Discussion
22.

In a junction diode, an equilibrium condition occurs when

A. Δngreater than Δp
B. Δnsmaller than Δp
C. Constant current flow
D. Optical amplification through stimulated emission
Answer» D. Optical amplification through stimulated emission
Discussion
23.

The carrier recombination lifetime becomes majority or injected carrier lifetime. State whether the given statement is true or false.

A. True
B. False
Answer» C.
Discussion
24.

The hole concentration in extrinsic materials is _________ electron concentration.

A. much greater than
B. lesser than
C. equal to
D. negligible difference with
Answer» B. lesser than
Discussion
25.

The excess density of electrons Δnand holes Δpin an LED is$

A. Equal
B. Δpmore than Δn
C. Δn more than Δp
D. Does not affects the LED
Answer» B. ‚âà√≠‚àö√Üpmore than ‚âà√≠‚àö√Ün
Discussion
26.

The absence of _______________ in LEDs limits the internal quantum efficiency.

A. Proper semiconductor
B. Adequate power supply
C. Optical amplification through stimulated emission
D. Optical amplification through spontaneous emission
Answer» D. Optical amplification through spontaneous emission
Discussion