Single Stage C-Band Erbium-Doped Fiber Amplifier (EDFA) Development and Performance Evaluation

Introduction

Erbium-Doped Fiber Amplifiers (EDFAs) are diode laser pumped optical fiber amplifiers which utilize erbium–doped fused silica fibers doped with trivalent erbium ions (Er⁺³) as the gain medium for boosting the transmitted optical signals (Zhang et al., 2008; Fontana, 1994; Dutta, 2015; Ter-Mikirtychev, 2014; Becker, Olsson, & Simpson, 1999; Baney, Gallion, & Tucker, 2000; Derrickson, 1998; Wang & Andrejco, 2005; Hentschel & Leckel, 1995; Zhang, Du, Xi, Li, & Zhao, 2008; Roy, Priye, & Kumar, 2013; Othman, Ismail, Mirsran, Said, & Sulaiman, 2013). EDFAs are widely used in long-range telecommunication networks for amplifying the transmitted signals in order to overcome the transmitted signal losses due to material attenuation, insertion loss (Alaruri, 2012) and splice loss (Alaruri, 2014) of fiber-optic components used in constructing the network. Other rare-earth elements such as ytterbium (Yb), neodymium (Nd), praseodymium (Pr), and thulium (Tm) can be also doped with fused silica fibers. The rare-earth element doped with fused silica determines the operating wavelength of the fiber laser or the fiber amplifier (Dutta, 2015; Ter-Mikirtychev, 2014). Other applications for EDFAs include material processing, micro machining, LIDAR and weapon systems (Fontana, 1994; Dutta, 2015; Ter-Mikirtychev, 2014; Becker, Olsson, & Simpson, 1999).

There are two types of EDFAs that are widely used in the telecommunication networks, namely, C-band EDFAs and L-band EDFAs (Zhang et al., 2008; Fontana, 1994; Dutta, 2015; Ter-Mikirtychev, 2014; Becker, Olsson, & Simpson, 1999; Alaruri, 2012). The C-band EDFAs operate in the spectral region 1525 to 1565 nm whereas the L-band EDFAs operate in the spectral region 1571 to 1603 nm. Both the C and the L-band EDFAs can be pumped efficiently with diode lasers operating at 980 nm or 1480 nm in the co-propagating or the counter-propagating direction or in both directions.

In this paper, the construction of a single-stage C-band EDFA which incorporates a 11.4 m erbium-coil is described. A simplified derivation for the EDFA gain, NF and CE mathematical expressions is given. A discussion for the variations in signal gain and noise figure as a function of wavelength and laser pump powers is provided. Also, the EDFA conversion efficiency as a function of laser pump powers is presented. The obtained results indicate that the C-band EDFA has a higher gain and conversion efficiency than the L-band EDFA (Alaruri, 2012).