Fiber Optics & Physical Layer Technologies Flashcards

What is the maximum reach of 10GBASE-LR (10 Gigabit Ethernet over single-mode fiber) per IEEE 802.3ae?

Answer: 10 kilometers

10GBASE-LR uses 1310 nm light over single-mode fiber and is specified for reaches up to 10 km per IEEE 802.3ae.

In a Passive Optical Network (PON), what device splits the optical signal from the central office to multiple subscriber premises?

Answer: Optical splitter

A passive optical splitter divides the downstream optical signal from the OLT to multiple ONTs at subscriber locations without requiring electrical power.

What is the maximum downstream bandwidth per PON port in XGS-PON (10G Symmetrical PON)?

Answer: 10 Gbps

XGS-PON provides 10 Gbps symmetrical (downstream and upstream) bandwidth per PON port, per ITU-T G.9807.1.

What causes optical back-reflection in a fiber link, and how is it typically mitigated?

Answer: Fresnel reflection at fiber end faces and connectors; mitigated using angled physical contact (APC) connectors or index-matching gel

Fresnel reflections occur at any glass-air interface (connectors, splices) and can disrupt laser sources; APC connectors reduce this by angling the end face to redirect reflections.

In DSL technology, what does the term 'attenuation' refer to in the context of loop length?

Answer: The reduction in signal strength as the electrical signal travels over copper pairs, which increases with loop length

DSL performance degrades with loop length because the copper pair attenuates (weakens) the high-frequency signals, reducing achievable speed as distance from the DSLAM increases.

What type of cable is used in most US residential CATV (cable TV) and HFC networks to connect homes to the distribution network?

Answer: RG-6 coaxial cable

RG-6 coaxial cable is the standard drop cable used in HFC (Hybrid Fiber Coaxial) networks to connect homes to the coaxial distribution plant.