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A dual pumped L-band erbium-doped fiber amplifier (DPLB-EDFA) is investigated by solving the optical propagation equation that takes into account radial effects of the fiber and the rate equation in a steady-state two-level model with a weakly guided approximation. Applying an inversing method and a genetic algorithm, the DPLB-EDFA is optimized for dual pumped wavelengths and directions, fiber lengths, as well as radial distributions of the erbium concentration and core refractive index. There is evidence to show that the optimal pumping wavelengths of the DPLB-EDFA are different in two different pumping schemes. The optimized DPLB-EDFA is characterized by a gain peak wavelength of 1600 nm, a gain peak of ~34 dB, a bandwidth of 30-37 nm, and a noise figure of 3.5-3.7 dB. Such characteristics are superior as compared with those using conventional 1480-nm pumps with step indexes and radial-uniform erbium concentrations [ABSTRACT FROM PUBLISHER]

Silica-on-silicon erbium-doped waveguide amplifiers (EDWAs) fabricated by the sol-gel route are demonstrated. The preparation of stable sols is first described, with emphasis on identifying chemical routes that allow the incorporation of sufficient concentration of erbium without precipitation or gelation. Erbium-doped glasses containing various codopants, such as phosphorus, aluminum, germanium and ytterbium are formed and used in the construction of buried channel guide EDWAs. A range of optical measurements is presented, and the effects of the dopants in eliminating erbium ion quenching and improving pumping efficiency are evaluated. The best material system-Er/Yb codoped aluminophosphosilicate glass-has low background loss and a net gain of 1.1 dB/cm. [ABSTRACT FROM PUBLISHER]

Very high-concentration erbium (Er)-doped fiber (EDF) codoped with high-concentration alumina (Al) for an efficient L-band EDFA has been developed. A high gain per unit length of 2.34 dB/m and a gain tilt of only 0.68 dB over a 30 nm bandwidth can be realized with a very short fiber length. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 27: 60–61, 2000. [ABSTRACT FROM AUTHOR]