Performance Optimization Of Er³⁺/Yb³⁺ Co-doped Double-cladding Optical Fiber

In recent years, as the increasing requirements for information, its transmission rate develops from Mbps to more than Tbps, in high power distribution systems such as DWDM, CATV and FTTH, optical fiber amplifiers are required higher saturation output power. Ordinary erbium-doped fiber amplifiers depend on single-mode laser diode pump, as its output power is to small too meet the requirements of amplifying multi wavelength signal, then, Er3+/Yb3+co-doped optical fiber amplifier(EYDFA) which based on double-cladding technology have emerged. Research of double cladding fiber is a huge breakthrough, which has played an important part in improving the output power of optical fiber amplifiers. Cladding fiber does not require pump laser to be single-mode, instead of coupling directly into optical fiber, pump only has to couple into the cladding, which have greatly improved the absorption area and efficiency, so multi-mode laser with high power can be used as pump source.First, this paper begins with the development history of optical fiber amplifier and application prospect of high power EYDFA. It introduces the structure and major advantages of double-cladding fiber, analyzes the influences of doping concentration of Er3+/Yb3+to the fiber characteristics and energy level structure of Er3+/Yb3+system, describes some related performance parameters of double cladding Er3+/Yb3+co-doped optical fiber amplifier, and upon the rate equation and power transmission equation, deeply discusses the theory model of EYDFA. Then does numerical simulation about the effect of the optical fiber length, pump power, signal power and doping concentration on gain of the optical fiber amplifier, and selects optimal parameters for the amplifier by analyzing the simulation result. Finally, to improve the output stability of EYDFA, this paper has simulated and proved the effectiveness of a method, which curbs Amplifier Spontaneity Eradiate (ASE) of Yb3+by co-seeding the high power EYDFA with an auxiliary signal in the1.0μm band, then analyzed the influence of the wavelength of the auxiliary signal on EYDFA.