Investigation of Broadband S-Band to L-Band Erbium-Doped Fiber Amplifier (EDFA) Module

Abstract

This chapter presents three sections that describe the broadband S-band to L-band erbi‐ um-doped fiber amplifier modules. In the first section, an S-band gain-clamped erbiumdoped fiber amplifier (EDFA) module, employing a fiber Bragg grating (FBG) to act as a reflected element for generating a saturated tone injected into the EDFA module by using forward optical feedback method, is proposed. Moreover, the output performance of the gain and noise figure (NF) in the proposed gain-clamped S-band EDFA has been dis‐ cussed in the wavelength range of 1478–1520 nm. In the second section, we demonstrate experimentally a gain-flattened two-stage erbium-based fiber amplifier (EBFA) module, which is composed of by an erbium-doped waveguide amplifier (EDWA) and a C-band EDFA in serial structure. In an operation range of 1528–1562 nm, the entire gain is larger than 35 dB and the observed NF is between 5.5 and 6.7 dB. Moreover, ±1.1 dB maximum gain variation is also obtained for the input signal power of -25 dBm. Hence, the pro‐ posed fiber amplifier not only enhances the gain but also achieves the flatness in the wavelength region. In the final section, a broadband hybrid two-stage fiber amplifier, which is composed by a C-band EDFA and a C-band semiconductor optical amplifier (SOA) in serial scheme, is investigated experimentally. Here, we only use a 3 m long erbi‐ um-doped fiber (EDF) serving as a preamplifier to increase the gain and reduce the noise figure. Therefore, the proposed hybrid amplifier achieves a 110 nm effectively amplifica‐ tion of 1500–1610 nm (from Sto L-band). In addition, the output performance of gain and NF in the proposed fiber amplifier has also been discussed.