Abstract

The enormous progress of erbium-doped fiber amplifiers (EDFAs) is accelerating the pace of deploying multigigabit-per-second long-haul undersea and terrestrial lightwave transmission links and various fiber-optic and wavelength-division-multiplexed (WDM) systems. The impact of fiber-optic amplifiers (FOA) on broadband local-, metropolitan-, and wide-area networks looms even larger. FOAs can simultaneously enhance network capacity, operational flexibility, and network functionality at potentially low cost. The large-quantity usage of interoffice trunks, broadband distribution, and switching networks demand FOAs with high-volume manufacturability, affordable cost, high reliability, and compact size. For high-speed and broadband systems, the FOAs must have very low polarization-mode dispersion (PMD) and polarization-dependent gain (PDG). Currently available amplifiers, as depicted in Fig. 1, contain several separate optical components: optical isolators, WDM couplers, tap couplers, and photodetectors. The components must be linked by fiber splicing, which creates additional loss and potential reliability problems.

© 1995 Optical Society of America