Fiber optic cables manufactured in a production unit need to undergo several mechanical tests to ensure their suitability to use in outdoor environment. While some tests are intended to assure the capability to use in outdoor environment, there are some tests that assure their suitability with the installation machines used for deployment. Sheave test is one of such tests. Sheave test is a kind of mechanical test which tests the strength of cable and its sheath to withstand the repeated movements through the sheaves.
Steel tapes are used for corrugation of fiber optic cables to provide extra mechanical strength to the fiber optic cables that is required for some installation conditions. ECCS tape or Electrolytically Chrome Coated Steel tape or Stainless Steel tapes comes in rolls of 1 or 2 kilometers in length. But fiber optic cable lengths during production are usually in lengths of 2, 4 or 6 kilometers.
Fiber optic cables installed near to the high voltage power cables are exposed to effects such as Tracking, Dry brand arcing, Corona effect and Flashover. This article is an attempt to deal with such effects on fiber optic cables. Generally when we talk about the advantageous of fiber optic cables over other metallic media for telecommunications, we say optical fiber cables are free from electro-magnetic influences. That is true as far as the communication signals are concerned.
Most EDFAs provide 20–25 dB amplification over a length of 10 m through a relatively high density of dopants (~500 parts per million). Since such EDFAs compensate for losses accumulated over 80–100 km in a relatively short distance of 10–20 m, they are referred to as the lumped amplifiers. Similar to the case of Raman amplification, fiber losses can also be compensated through distributed amplification. In this approach, the transmission fiber itself is lightly doped (dopant density ~50 parts per billion) to provide the gain distributed over the entire fiber length such that it compensates for fiber losses locally. Such an approach results in a virtually transparent fiber at a specific wavelength when the fiber is pumped using the bidirectional pumping configuration.