CTE CTE Fiber Optics & Transmission Systems 2

Question 1

What does the term 'dispersion-shifted fiber' (DSF, ITU-T G.653) refer to?

Accepted Answer

Fiber designed to shift the zero-dispersion wavelength from 1310 nm to 1550 nm

Answer

DSF moves the zero-dispersion wavelength to 1550 nm to minimize dispersion at the lowest-attenuation window, though it suffers from four-wave mixing in DWDM use.

Question 2

In a passive optical network (PON), what does the optical splitter enable?

Accepted Answer

It allows a single feeder fiber from the OLT to serve multiple ONTs without active electronics

Answer

The passive optical splitter divides (and combines) light between the OLT's feeder fiber and multiple ONT drop fibers using no active electronics, reducing cost and maintenance.

Question 3

What is the purpose of dispersion compensation fiber (DCF) used in long-haul fiber links?

Accepted Answer

To introduce negative dispersion that cancels accumulated positive chromatic dispersion

Answer

DCF has large negative dispersion coefficient (~−80 to −100 ps/nm·km), intentionally added to counteract positive chromatic dispersion accumulated over standard SMF spans.

Question 4

Which optical connector type is most commonly specified in US carrier outside plant (OSP) single-mode fiber installations due to its push-pull latching and low insertion loss?

Accepted Answer

SC connector

Answer

The SC (Subscriber Connector) with push-pull coupling is widely used in US carrier OSP for its low insertion loss (<0.3 dB), repeatability, and compact form factor.

Question 5

In SONET/SDH terminology, what does the STS-1 signal rate of 51.84 Mbps represent?

Accepted Answer

The base rate of the SONET hierarchy from which higher rates (STS-3, STS-12…) are derived by multiplexing

Answer

STS-1 at 51.84 Mbps is the fundamental SONET building block; higher rates (OC-3 = 155.52 Mbps, OC-48 = 2.488 Gbps, etc.) are integer multiples of this base.

CTE - Certified Telecommunications Engineer Practice Test

CTE - Certified Telecommunications Engineer Practice Test

CTE CTE Fiber Optics & Transmission Systems 2