Abstract

Various schemes for long-wavelength-band (L-band) erbium-doped fiber amplifiers (EDFAs) have been reported to enhance the amplifier characteristics by efficient use of strong but wasted backward amplified spontaneous emission (ASE)[1][2]. In this paper we propose and demonstrate a two-stage L-band EDFA configuration shown in Fig 1(a). A reflective-type first-stage amplifier is accommodated in the configuration to obtain strong ASE and to use it as a pump source for the second-stage amplifier. We compare its characteristics to those of a previous L-EDFA configuration shown in Fig 1(b) because the previous L-EDFA had better gain and noise figure (NF) than a conventional L-EDFA wasting backward ASE [2]. We used 15 and 80 m-long erbium-doped fiber with an erbium concentration of 270 ppm, and an absorption coefficient of 5.5 dB/m at 1530 nm for EDF1 and EDF2, respectively.

© 2001 EPS