Theoretical Studies on Dynamic Characteristics of Yb-Sensitized Er-Doped Garnet Crystal Waveguide-Type Optical Amplifiers

Abstract

Amplifiers doped with Ytterbium and Erbium ions are given increasing attention for amplification of signals in the present communication wavelength band of 1.55 μm. Sensitization of Er-doped amplifiers has many advantages such as the possibility of using broader pumping wavelength range. In this paper a thin-film waveguide amplifier based on Er-Yb codoped Garnet crystals is proposed and steady state and transient amplification characteristics, studied numerically using time-dependent rate equations are presented. Understanding the dynamic characteristics of the integrated optic waveguide amplifiers is necessary when the input signal is modulated in various formats. Amplification and pulse distortion effects of short signal pulses are presented, which are shown to be related to the lifetime of the excited states. Comparison is made between the gain characteristics of Er and Er-Yb doped waveguide amplifiers.