A BH can have anything from a single electron to several electrons.
1.True
2.False
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
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%
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
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
A perfect semiconductor crystal containing no impurities or lattice defects is called as __________
1.Intrinsic semiconductor
2.Extrinsic semiconductor
3.Excitation
4.Valence electron
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
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
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
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.
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
Couplers insertion loss is same as that of excess loss.
1.True
2.False
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
Dot-in-well device is also known as __________
1.DH lasers
2.BH lasers
3.QD lasers
4.Gain guided lasers
How many fabrication techniques are used for 3 port fiber couplers?
1.One
2.Two
3.Three
4.Four
How many manufacturing methods are used for producing multimode fiber star couplers?
1.Two
2.One
3.Three
4. Five
How many types of multiport optical fiber couplers are available at present?
1.Two
2.One
3.Four
4.Three
In a multimode fiber, much of light coupled in the fiber from an LED is ____________
1.Increased
2.Reduced
3.Lost
4.Unaffected
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
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
In optical fiber communication _____________ major types of LED structures are used.
1.2
2.4
3.6
4.3
In surface emitter LEDs, more advantage can be obtained by using ____________
1.BH structures
2.QC structures
3.DH structures
4.Gain-guided structure
Internal absorption in DH surface emitter Burros type LEDs is ____________
1.Cannot be determined
2.Negligible
3.High
4.Very low
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
Mesa structured SLEDs are used ____________
1.To reduce radiance
2.To increase radiance
3.To reduce current spreading
4.To increase current spreading
Multi-quantum devices have superior characteristics over __________
1.BH lasers
2.DH lasers
3.Gain guided lasers
4.Single-quantum-well devices
Optical fiber couplers are also called as ________________
1.Isolators
2.Circulators
3.Directional couplers
4.Attenuators
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
Quantum well lasers are also known as __________
1.BH lasers
2.DH lasers
3.Chemical lasers
4.Gain-guided lasers
Quantum well lasers are providing high inherent advantage over __________
1.Chemical lasers
2.Gas lasers
3.Conventional DH devices
4.BH device
Some refractive index variation is introduced into lateral structure of laser.
1.True
2.False
Strip geometry of a device or laser is important.
1.True
2.False
The active layer of E-LED is heavily doped with ____________
1.Zn
2.Eu
3.Cu
4.Sn
The amount of radiance in planer type of LED structures is ____________
1.Low
2.High
3.Zero
4.Negligible
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
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
The majority of the carriers in a p-type semiconductor are __________
1.Holes
2.Electrons
3.Photons
4. Neutrons
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
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
The recombination in indirect band-gap semiconductors is slow.
1.True
2.False
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
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
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
What is the strip width of injection laser?
1.12 μm
2.11.5 μm
3.Less than 10 μm
4.15 μm
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
Which impurity is added to gallium phosphide to make it an efficient light emitter?
1.Silicon
2.Hydrogen
3.Nitrogen
4.Phosphorus
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
________ 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
_______________ 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
_________________ is used when the optical emission results from the application of electric field.
1.Radiation
2.Efficiency
3.Electro-luminescence
4.Magnetron oscillator