Expanded Beam Connectors

This set of Optical Communications Multiple Choice Questions & Answers (MCQs) focuses on “Expanded Beam Connectors”.

1. What is the use of interposed optics in expanded beam connectors?
a) To achieve lateral alignment less critical than a butt-joined fiber connector
b) To make a fiber loss free
c) To make a fiber dispersive
d) For index-matching

2. The expanded beam connectors use ____________ for beam expansion and reduction.
a) Square micro-lens
b) Oval micro-lens
c) Spherical micro-lens
d) Rectangular micro-lens

3. Lens-coupled expanded beam connectors exhibit average losses of _________ in case of single mode and graded index fibers.
a) 0.3 dB
b) 0.7 dB
c) 0.2 dB
d) 1.5 dB

4. Sapphire ball lens expanded beam design is successful than spherical lens coupled design.
a) True
b) False

5. The fiber is positioned at the ________ of the lens in order to obtain a collimated beam and to minimize lens-to-lens longitudinal misalignment effects.
a) Aperture
b) Focal length
c) Curve
d) Exterior circumference

6. ___________ exhibits a parabolic refractive index profile with a maximum at the axis similar to graded index fiber.
a) Lens coupled design
b) Sapphire ball lens
c) Spherical micro-lens
d) GRIN-rod lens

7. The GRIN-rod lens can produce a collimated output beam with a divergent angle αof between _____________ from a light source situated on, or near to, the opposite lens face.
a) 1 to 5 degrees
b) 9 to 16 degrees
c) 4 to 8 degrees
d) 25 to 50 degrees

8. In the given equation, if r is the radial distance, n is the refractive index; what does z stands for?

dr2/dz2 = (1/n) (d n/dr)

a) Focal length
b) Distance along the optical axis
c) Axial angle
d) Diameter

9. The majority of the GRIN-rod lenses have diameters in the range of ____________
a) 2 to 2.5 mm
b) 3 to 4 mm
c) 0.1 to 0.4 mm
d) 0.5 to 2 mm

10. Which of the following factors does not cause divergence of the collimated beam from a GRIN-rod lens?
a) Lens cut length
b) Size of fiber core
c) Refractive index profile
d) Chromatic aberration

11. GRIN-rod lens connectors have loss characteristics that are independent of the modal power distribution in the fiber.
a) True
b) False

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