Abstract

One of the attractions of an Er-doped optical fiber (EDF) is the insensitivity of its gain to signal and pump polarizations. In practice, however, the gain of Er-doped optical fiber amplifiers (EDFAs) fluctuates because of polarization fluctuations in polarization-sensitive components, such as wavelength-division-multiplexing (WDM) couplers, isolators, and modulators, used in the EDFAs. In addition, other applications of EDFs, such as fiber-ring lasers¹ and nonlinear amplifying-loop mirrors,² require polarization maintenance. In this paper we propose a new and cost-effective structure for a polarization- maintaining (PM) EDF with a twin-peak core (TPC), and we report a high-performance TPC fiber amplifier using a mode- field-diameter-adjusting (MFDA) technique.³

© 1994 Optical Society of America