Erbium Doped Fiber Lasers for Long Distance Communication Using Network of Fiber Optics

Abstract

A fiber doped with erbium laser is used in long distance communication over networks of fiber optics. Especially, in under water communication links where optical signals can be amplified by joining erbium-doped fiber at appropriate locations in the network of the fiber. Thus, a signal, when optically transmitted will get amplified and this will be useful when the signal travels between continents. There is no need for converting an optical signal into an electrical signal, amplified and then reintroduced into the fiber for transmission. The latest research trend is to produce ultra-short pulse widths of the order of 100fs and with a pulse repetition rate of the order of 10GHz. Here I have used an Er3+ doped silica fiber for optical pumping λ=0.98µm or λ=1.48µm wavelength using radiation from a diode laser [Fig. 1]. A coupler was used to select the wavelength, which permits this light to reach the optical fiber transmission system, without disturbing the signal. The optical fiber is spliced into the transmission lines, which acts as an optical isolator. This fiber is constantly pumped by the diode laser. When the pulses pass through the system, they get amplified, while the pump light is reduced.