Abstract

Erbium-doped fiber amplifiers (EDFAs) are very attractive devices at the wavelength of 1.55 µm because they have many abilities such as high gain over 20 dB, small temperature dependence and polarization-insensitive.^1),2) Pumping by laser diodes (LDs) is strongly required in practical EDFAs. Two types of LDs (wavelength of 0.98 µm and 1.48 µm) have been investigated for pumping sources. 0.98 µm pumping gives high pumping efficiency and low power consumption.³⁾ On the other hand, the gain spectrum is flatter by the use of 1.48 µm pumping.⁴⁾ Furthermore, high reliability can be expected for 1.48 µm pump LDs.⁵⁾ Considering the reliability for EDFA-systems, however, it is important to develop a high reliable pump LD under high output power operation more than 100 mW.

© 1990 Optical Society of America