________ couplers combine the different wavelength optical signal onto the fiber or separate the different wavelength optical signal output from the fiber.
1.3-port
2.2*2-star
3.WDM
4.Directional
Posted Date:-2022-05-05 21:45:13
_______________ method does not require a leaky mode correction factor or equal mode excitation.
1.Bending-reference
2.Power step method
3.Alternative test method
4.Refracted near-field method
Posted Date:-2022-05-05 21:29:21
_________________ is used when the optical emission results from the application of electric field.
1.Radiation
2.Efficiency
3.Electro-luminescence
4.Magnetron oscillator
Posted Date:-2022-05-05 22:17:17
A _____________ coupler comprises a number of cascaded stages, each incorporating three or four-port FBT couplers to obtain a multiport output.
1.Star
2.Ladder
3.WDM
4.Three-port
Posted Date:-2022-05-05 21:50:19
A BH can have anything from a single electron to several electrons.
1.True
2.False
Posted Date:-2022-05-05 22:14:05
A double-channel planar buried hetero-structure (DCP BH) has a planar active region, the confinement material is?
1.Alga AS
2.InGaAsP
3.GaAs
4.SiO2
Posted Date:-2022-05-05 22:08:23
A four-port FBT coupler has 60μW optical power launched into port one. The output powers at ports 2, 3, 4 are 0.0025, 18, and 22 μW respectively. Find the split ratio?
1.42%
2.46%
3.52%
4.45%
Posted Date:-2022-05-05 21:48:24
A four-port multimode fiber FBT coupler has 50 μW optical power launched into port 1. The measured output power at ports 2,3 and 4 are 0.003, 23.0 and 24.5 μW respectively. Determine the excess loss.
1.0.22 dB
2.0.33 dB
3.0.45 dB
4.0.12 dB
Posted Date:-2022-05-05 21:47:47
A number of three-port single-mode fiber couplers are used in the fabrication of a ladder coupler with 16 output ports. The three-port couplers each have an excess loss of 0.2 dB along with a splice loss of 0.1 dB at the interconnection of each stage. Determine the excess loss.
1.1.9 dB
2.1.4 dB
3.0.9 dB
4.1.1 dB
Posted Date:-2022-05-05 21:56:45
A perfect semiconductor crystal containing no impurities or lattice defects is called as __________
1.Intrinsic semiconductor
2.Extrinsic semiconductor
3.Excitation
4.Valence electron
Posted Date:-2022-05-05 22:14:52
As compared to planar LED structure, Dome LEDs have ______________ External power efficiency ___________ effective emission area and _____________ radiance.
1.Greater, lesser, reduced
2.Higher, greater, reduced
3.Higher, lesser, increased
4.Greater, greater, increased
Posted Date:-2022-05-05 21:58:48
Better confinement of optical mode is obtained in __________
1.Multi Quantum well lasers
2.Single Quantum well lasers
3.Gain guided lasers
4.BH lasers
Posted Date:-2022-05-05 22:12:38
Buried hetero-junction (BH) device is a type of _____________ laser where the active volume is buried in a material of wider band-gap and lower refractive index.
1.Gas lasers.
2.Gain guided lasers.
3.Weak index guiding lasers.
4.Strong index guiding lasers.
Posted Date:-2022-05-05 22:07:05
Calculate the splitting loss if a 30×30 port multimode fiber star coupler has 1 mW of optical power launched into an input port.
1.13 dB
2.15 dB
3.14.77 dB
4.16.02 dB
Posted Date:-2022-05-05 21:49:39
Couplers insertion loss is same as that of excess loss.
1.True
2.False
Posted Date:-2022-05-05 21:47:11
DH surface emitter generally give ____________
1.More coupled optical power
2.Less coupled optical power
3.Low current densities
4.Low radiance emission into-fiber
Posted Date:-2022-05-05 22:01:04
Dot-in-well device is also known as __________
1.DH lasers
2.BH lasers
3.QD lasers
4.Gain guided lasers
Posted Date:-2022-05-05 22:13:43
How many fabrication techniques are used for 3 port fiber couplers?
1.One
2.Two
3.Three
4.Four
Posted Date:-2022-05-05 21:45:57
How many manufacturing methods are used for producing multimode fiber star couplers?
1.Two
2.One
3.Three
4. Five
Posted Date:-2022-05-05 21:48:58
How many types of multiport optical fiber couplers are available at present?
1.Two
2.One
3.Four
4.Three
Posted Date:-2022-05-05 21:43:36
In a multimode fiber, much of light coupled in the fiber from an LED is ____________
1.Increased
2.Reduced
3.Lost
4.Unaffected
Posted Date:-2022-05-05 22:01:59
In Buried hetero-junction (BH) lasers, the optical field is confined within __________
1.Transverse direction
2.Lateral direction
3.Outside the strip
4.Both transverse and lateral direction
Posted Date:-2022-05-05 22:07:42
In multimode injection lasers, the construction of current flow to the strip is obtained in structure by __________
1.Covering the strip with ceramic
2.Intrinsic doping
3.Implantation outside strip region with protons
4.Implantation outside strip region with electrons
Posted Date:-2022-05-05 22:05:23
In optical fiber communication _____________ major types of LED structures are used.
1.2
2.4
3.6
4.3
Posted Date:-2022-05-05 21:58:09
In surface emitter LEDs, more advantage can be obtained by using ____________
1.BH structures
2.QC structures
3.DH structures
4.Gain-guided structure
Posted Date:-2022-05-05 21:59:50
Internal absorption in DH surface emitter Burros type LEDs is ____________
1.Cannot be determined
2.Negligible
3.High
4.Very low
Posted Date:-2022-05-05 22:00:27
It is a device that distributes light from a main fiber into one or more branch fibers.
1.Optical fiber coupler
2.Optical fiber splice
3.Optical fiber connector
4.Optical isolator
Posted Date:-2022-05-05 21:32:49
Mesa structured SLEDs are used ____________
1.To reduce radiance
2.To increase radiance
3.To reduce current spreading
4.To increase current spreading
Posted Date:-2022-05-05 22:03:21
Multi-quantum devices have superior characteristics over __________
1.BH lasers
2.DH lasers
3.Gain guided lasers
4.Single-quantum-well devices
Posted Date:-2022-05-05 22:13:13
Optical fiber couplers are also called as ________________
1.Isolators
2.Circulators
3.Directional couplers
4.Attenuators
Posted Date:-2022-05-05 21:42:58
Problems resulting from parasitic capacitances can be overcome __________
1.Through regrowth of semi-insulating material
2.By using oxide material
3.By using a planar InGaAsP active region
4.By using a AlGaAs active region
Posted Date:-2022-05-05 22:10:33
Quantum well lasers are also known as __________
1.BH lasers
2.DH lasers
3.Chemical lasers
4.Gain-guided lasers
Posted Date:-2022-05-05 22:11:12
Quantum well lasers are providing high inherent advantage over __________
1.Chemical lasers
2.Gas lasers
3.Conventional DH devices
4.BH device
Posted Date:-2022-05-05 22:11:45
Some refractive index variation is introduced into lateral structure of laser.
1.True
2.False
Posted Date:-2022-05-05 22:06:30
Strip geometry of a device or laser is important.
1.True
2.False
Posted Date:-2022-05-05 22:12:07
The _______ method is the most commonly used method for the determination of the fiber refractive index profile.
1.Refracted near-field method
2.Bending-reference
3.Power step method
4.Alternative test method
Posted Date:-2022-05-05 21:30:50
The active layer of E-LED is heavily doped with ____________
1.Zn
2.Eu
3.Cu
4.Sn
Posted Date:-2022-05-05 22:04:31
The amount of radiance in planer type of LED structures is ____________
1.Low
2.High
3.Zero
4.Negligible
Posted Date:-2022-05-05 21:57:35
The energy-level occupation for a semiconductor in thermal equilibrium is described by the __________
1.Boltzmann distribution function
2.Probability distribution function
3.Fermi-Dirac distribution function
4.Cumulative distribution function
Posted Date:-2022-05-05 22:15:28
The InGaAsP is emitting LEDs are realized in terms of restricted are ____________
1.Length strip geometry
2.Radiance
3.Current spreading
4.Coupled optical power
Posted Date:-2022-05-05 22:03:57
The majority of the carriers in a p-type semiconductor are __________
1.Holes
2.Electrons
3.Photons
4. Neutrons
Posted Date:-2022-05-05 22:16:40
The optical power coupled from one fiber to another is limited by ____________
1.Numerical apertures of fibers
2.Varying refractive index of fibers
3.Angular power distribution at source
4.Number of modes propagating in each fiber
Posted Date:-2022-05-05 21:44:23
The overall power conversion efficiency of electrical lens coupled LED is 0.8% and power applied 0.0375 V. Determine optical power launched into fiber.
1.0.03
2.0.05
3.0.3
4.0.01
Posted Date:-2022-05-05 22:02:40
The recombination in indirect band-gap semiconductors is slow.
1.True
2.False
Posted Date:-2022-05-05 22:17:43
The techniques by Burros and Dawson in reference to homo structure device is to use an etched well in GaAs structure.
1.True
2.False
Posted Date:-2022-05-05 21:59:14
What is done to create an extrinsic semiconductor?
1.Refractive index is decreased
2.Doping the material with impurities
3.Increase the band-gap of the material
4.Stimulated emission
Posted Date:-2022-05-05 22:16:08
What is the strip width of injection laser?
1.12 μm
2.11.5 μm
3.Less than 10 μm
4.15 μm
Posted Date:-2022-05-05 22:06:08
When considering source-to-fiber coupling efficiencies, the ________ is an important parameter than total output power.
1.Numerical aperture
2.Radiance of an optical source
3.Coupling efficiency
4.Angular power distribution
Posted Date:-2022-05-05 21:32:09
Which impurity is added to gallium phosphide to make it an efficient light emitter?
1.Silicon
2.Hydrogen
3.Nitrogen
4.Phosphorus
Posted Date:-2022-05-05 22:18:19
Which is the most common method for manufacturing couplers?
1.Wavelength division multiplexing
2.Lateral offset method
3.Semitransparent mirror method
4.Fused bi-conical taper (FBT) technique
Posted Date:-2022-05-05 21:46:46