A multimode graded index fiber exhibits total pulse broadening of 0.2 µsec over a distance of 10Km. Estimate the maximum possible bandwidth assuming that there is no inter-symbol interference.
5 MHZ 0.0%
2.5 MHZ 0.0%
10 MHZ 0.0%
1 MHZ 100.0%
Avalanche photodiodes are ________.
less sensitive than simple photodiodes 0.0%
more sensitive than simple photodiodes 100.0%
cheaper than simple photodiodes 0.0%
less complex in structure than simple photodiodes 0.0%
COBRA (commutateur optique binaire rapide) is an ________.
optical fiber 0.0%
optical source 0.0%
optical detector 100.0%
optical switch 0.0%
Dark line defects (DLDs) occur when:
non-radiative electron-hole recombination occurs 0.0%
mobile impurities are displaced into the active region of LASER 100.0%
all modes are not stabilized 0.0%
all modes are not polarized 0.0%
Dark spot defects (DSD's) occur in:
Non-semiconductor LASER 0.0%
Fiber LASER 100.0%
Glass fiber LASER 0.0%
Injection LASER 0.0%
Dispersion in optical fibers causes distortion in _______.
analog signals only 0.0%
digital signals only 100.0%
both analog and digital signals 0.0%
infra-red signals only 0.0%
Dispersion is low in the __________.
Multimode step index fiber 100.0%
Single mode step index fiber 0.0%
Two mode step index fiber 0.0%
None of the above 0.0%
Dispersion is the lowest in a________.
Multimode step-index fiber 0.0%
Multimode graded-index fiber 100.0%
Single-mode step-index fiber 0.0%
Silicon fiber 0.0%
FDDI can support a data rate of
10 Mbps 0.0%
10 Gbps 0.0%
100 Mbps 100.0%
1000 Mbps 0.0%
FDDI is _______.
Fiber dual data interface 0.0%
Fiber distributed data interface 100.0%
Fiber dual data interchange 0.0%
Fiber distributed data interchange 0.0%
For a multimode optical graded index fiber, the profile parameter (α) will be equal to:
∞ 100.0%
Zero 0.0%
1 0.0%
2 0.0%
For a profile parameter (α)=1, the profile shape of refractive index for a graded index fiber will be _______.
triangular 0.0%
parabolic 100.0%
step 0.0%
circular 0.0%
For a step index fiber, relationship between numerical aperture (NA) and coupling efficiency (ηc) is ________.
a 0.0%
b 100.0%
c 0.0%
d 0.0%
For an ideal photo detector, the absorption coefficient must be ______.
low 0.0%
zero 0.0%
one 0.0%
large 100.0%
Germanium avalanche photodiodes can be used for _______.
longer wavelength operation 100.0%
shorter wavelength operation 0.0%
low output power operation 0.0%
minimum noise operation 0.0%
Germanium photodiodes are generally not preferred in the optical fiber system because of _________.
large current gain 0.0%
large voltage gain 0.0%
temperature dependence 0.0%
large dark current 100.0%
Graded-index fibers have:
a constant refractive index in the core 0.0%
a variable refractive index in the cladding 0.0%
a variable refractive index in the core 0.0%
None of these 100.0%
Homodyne detection is used for _______.
incoherent systems 100.0%
incandescent systems 0.0%
coherent systems 0.0%
analog systems 0.0%
Hydrogen absorption by optical fiber causes _______.
an increase in efficiency 0.0%
a decrease in optical fiber losses 0.0%
no effect 0.0%
an increase in optical fiber losses 100.0%
IEEE 802.5 is a/an ________.
Ethernet 0.0%
Token bus 0.0%
Token ring 100.0%
Token star 0.0%
In p-i-n photodiodes "i" stands for:
Internal 0.0%
Intrinsic 100.0%
Impurity 0.0%
None of the above 0.0%
Index optical fibers are sometimes referred to as:
Homogenous core fibers 100.0%
Heterogeneous core fibers 0.0%
Long fibers 0.0%
Short fibers 0.0%
Intermodal dispersion is less in a __________.
Multimode step index fiber 100.0%
Multimode graded index fiber 0.0%
Single mode step index fiber 0.0%
Single mode graded index fiber 0.0%
Intersymbol interference (ISI) in optical fibers occurs due to ______.
refraction 0.0%
scattering 100.0%
bending 0.0%
dispersion 0.0%
LASER stands for:
Light amplification by spontaneous emission of radiation 0.0%
Light amplification by stimulated emission of radiation 0.0%
Light amplification by straight emission of radiation 100.0%
None of the above 0.0%
LED is more suitable for analog transmission because of its _______.
linearity 0.0%
bandwidth (spectrum) 0.0%
modulation property 100.0%
output power 0.0%
Light emitting diodes (LED's) are:
Monochromatic incoherent sources 0.0%
Monochromatic coherent sources 0.0%
Incandescent light sources 0.0%
None of the above 100.0%
Macro bending losses in optical fibers can be reduced by designing the fibers with ________.
a smaller refractive index difference 0.0%
a fiber glass 100.0%
a silica glass 0.0%
a larger refractive index difference 0.0%
Metallic impurities are eliminated from optical fiber by:
Vapor axial deposition (VAD) method 100.0%
Modified chemical vapor deposition (MCVD)method 0.0%
Vapor-phase oxidation method 0.0%
Plasma-activated chemical vapor deposition (PCVD)method 0.0%
Mirrors are placed in LASER optical sources to maintain conditions for ________.
incoherence 0.0%
amplification 100.0%
modulation 0.0%
coherence 0.0%
Near-field scanning method is used to measure:
Fiber attenuation 100.0%
Fiber dispersion 0.0%
Fiber numerical aperture 0.0%
Fiber refractive index profile 0.0%
Numerical aperture (NA) is related to the refractive indexes of core (n1) and cladding (n2) when,
a 0.0%
b 100.0%
c 0.0%
d 0.0%
One polarization maintaining fiber operates at a wavelength of 1.5 µm and has a beat length of 0.6mm. Its modal birefringence is given by _______.
1.5 x 10-3 100.0%
3.5 x 10-3 0.0%
2.5 x 10-3 0.0%
4.5 x 10-3 0.0%
Optical bandwidth (OB) relates to electrical bandwidth (EB) when
OB<EB 0.0%
OB=EB 0.0%
OB>EB 100.0%
OB≥EB 0.0%
Optical time domain reflectometry (OTDR) is a/an ________.
attenuation measurement technique 100.0%
refractive index measurement technique 0.0%
field measurement technique 0.0%
core diameter measurement technique 0.0%
Quantum efficiency (η) is defined as
a 0.0%
b 0.0%
c 100.0%
d 0.0%
Rayleigh scattering is a ________.
non-linear scattering 100.0%
differential scattering 0.0%
cumulative scattering 0.0%
linear scattering 0.0%
Refer to the figure above. The critical angle at the core cladding interface is given by:
a 0.0%
b 0.0%
c 100.0%
d 0.0%
Scattering losses happen due to:
a rise in temperature 0.0%
imperfections in glass manufacturing process 100.0%
humidity 0.0%
bending of fiber 0.0%
Silicon reach through avalanche photodiodes has _______.
maximum absorption of photons 0.0%
maximum absorption of electrons 100.0%
maximum quantum efficiency 0.0%
minimum noise 0.0%
SOLITON is a/an ______.
type of optical fiber 100.0%
optical source 0.0%
optical detector 0.0%
pulse traveling in optical fiber 0.0%
SONET is _________.
Scattered optical network 0.0%
Synchronous optical network 0.0%
Stable optical network 0.0%
Silicon optical network 100.0%
Superluminescent LED's are preferred because of _______.
large spectral linewidth 0.0%
a directional output beam 0.0%
low output power 100.0%
small size 0.0%
Surface emitter LEDs have high radiance because _______.
a hemisphere of n type GaAs is formed around a diffused p-type region 0.0%
of p-type diffusion into the n-type substrate 0.0%
it restricts the emission to a small active region 0.0%
of n-type diffusion into the p-type substrate 100.0%
The cutback technique is a/an _______.
attenuation measurement technique 0.0%
refractive index measurement technique 100.0%
impurity measurement technique 0.0%
frequency measurement technique 0.0%
The fiber gyroscope is an ______.
Intrinsic fiber sensor 100.0%
Interferometer fiber sensor 0.0%
Extrinsic fiber sensor 0.0%
Extinction fiber sensor 0.0%
The first generation optical fibers are fabricated from:
Silica 0.0%
Oxides 0.0%
Gallium aluminum arsenide alloys 100.0%
Plastic 0.0%
The information carrying capacity of optical fibers is in the range of:
MHZ 100.0%
mHZ 0.0%
GHZ 0.0%
µHZ 0.0%
The LASER is a/an
incoherent device 0.0%
switching device 0.0%
threshold device 0.0%
incandescent device 100.0%
The Nd:YAG LASER is a/an_______.
non semiconductor laser 0.0%
semiconductor laser 0.0%
injection laser 100.0%
directional laser 0.0%
The output power of a LASER is greater than that of a LED because of _____.
stimulated emission 0.0%
spontaneous emission 100.0%
straight emission 0.0%
None of the above 0.0%
The population inversion phenomenon in optical sources occurs when _________.
the population of atoms in the upper energy level is greater than in the lower energy level 0.0%
the population of atoms in the lower energy level is greater than in the upper energy level 0.0%
the population of atoms in the upper and lower energy levels is equal 0.0%
None of the above 100.0%
The rays which travel in a helical path through an optical fiber are called ______.
refracted rays 0.0%
reflected rays 0.0%
infra-red rays 0.0%
skew rays 100.0%
The refractive index is defined as the ratio of ____________.
the velocity of light in a vacuum to the velocity of light in the medium 0.0%
the velocity of light in the medium to the velocity of sound in a vacuum 100.0%
the velocity of light in the medium to the velocity of light in a vacuum 0.0%
The vapor-phase deposition technique is used to produce _______.
fiber-rich glasses 100.0%
silica-rich glasses 0.0%
oxide-rich glasses 0.0%
carbonate-rich glasses 0.0%
Total internal reflection takes place at angles ________.
greater than the critical angle 100.0%
less than the critical angle 0.0%
equal to the critical angle 0.0%
None of the above 0.0%
What does TPON stand for?
Telephony on a pure optical network 0.0%
Telephony on a plastic optical network 0.0%
Telephony on a polarized optical network 100.0%
Telephony on a passive optical network 0.0%
What happens when dispersion occurs?
Output transmitted pulse broadens 0.0%
Output transmitted pulse shortens 0.0%
Output transmitted pulse gets completely eliminated 100.0%
None of the above 0.0%
What is signal attenuation in an optical fiber where P1=Input power and P0=Output power
a 0.0%
b 0.0%
c 100.0%
None of the above 0.0%
What is the relationship between refractive index (n1) of core and refractive index (n2) of cladding for an optical fiber?
n1 < n2 0.0%
n1 = n2 0.0%
n1 < n2 100.0%
n1 > n2 0.0%
What is the thermal noise current it in a resistor R expressed in its mean square value? where, K is Boltzmann's constant, T is absolute temperature and B is the bandwidth
a 0.0%
b 0.0%
c 100.0%
d 0.0%
What would the optical return loss (ORL) be defined as when r-fresnal reflection occurs at a fiber-air interface?
ORL= -10log10r 0.0%
ORL= -20log10r 100.0%
ORL= -30log10r 0.0%
ORL= -10loger 0.0%
When microwave frequency rather than radio frequency subcarriers are employed, the strategy is usually referred to as ______.
Time division multiplexing 0.0%
Frequency division multiplexing 0.0%
Code-division multiplexing 100.0%
Subcarrier multiplexing (SCM) 0.0%
When optical power is incident on the photo detector during the 0 bit period, then the system is said to exhibit _______.
a non-zero extinction ratio 0.0%
a zero extinction ratio 100.0%
an infinity extinction ratio 0.0%
an infinity absorption ratio 0.0%
Which of the following is a characteristic of an injection LASER?
Frequency Chirp 0.0%
Amplification 100.0%
Frequency modulation 0.0%
Output power 0.0%
Which of the following is a fiber dispersion measurement method?
Time domain measurement 100.0%
Interferometric method 0.0%
Refracted near field method 0.0%
Reflected near field method 0.0%
Which of the following is an Optical System Design Software?
MATLAB 0.0%
COMSIM 0.0%
Photonic Transmission Design Suite (PTDS) 100.0%
ORCAD 0.0%
Which one of the following is a type of non-linear scattering?
Stimulated Raman scattering (SRS) 0.0%
Rayleigh scattering 0.0%
Mie scattering 0.0%
Ultraviolet scattering 100.0%
Which phenomenon does not let light rays escape an optical fiber?
Total internal reflection 0.0%
Total internal refraction 0.0%
Total internal diffraction 100.0%
Total internal attenuation 0.0%