Amplification Characteristics of Polarization-Maintaining Erbium-Doped Optical Fiber

A polarization-maintaining erbium-doped fiber (PM-EDF) based on the PANDA (Polarization-maintaining AND Absorption-reducing) type fiber technology has been developed as an amplification medium of a polarization-maintaining optical amplifier for 1550 nm band. Detail amplification and polarization characteristics of the PM-EDF have been evaluated for the first time. The carefully designed PM-EDF amplifies the optical signal with a high gain and low noise figure, keeping the state of polarization through the fiber. The amplification performance of the newly developed PM-EDF is the same as that of the conventional erbium doped amplifiers except the polarization characteristics. The achieved characteristics are 35 dB gain for small signal, 4.8 dB noise figure, 70% slope efficiency, 30 dB of polarization extinction ratio even in a fiber coil of 15 mm in diameter. Polarization hole burning is also reported.