Doped fiber amplifier (The typical representative: EDFA) Erbium-doped fiber amplifier (EDFA) is the most widely used fiber-optic amplifiers, mainly made of Erbium-doped fiber (EDF), pump light source, optical couplers, optical isolators, optical filters and other components.
Noun. 1. national income-the total value of all income in a nation (wages and profits and interest and rents and pension payments) during a given period (usually 1 yr).
National insurance (NI) - General information. National insurance (NI) is a contribution made by the employee and employer to cover benefits such as statutory maternity, paternity and adoption pay and state pensions. The rate at which NI is due depends on the employee's circumstances, and is governed by the employee's NI category. NI earnings bands.