Theoretical Design Of Yb-Er Codoped Chalcogenide Waveguide Amplifier On SiO₂Substrate

In recent years, with the rapid development of Internet and digital communications business, EDWA needs higher power amplification and wider bandwidth to meet signal transmission of long distance, multi-channel and large information, all optical communication network is gradually to the personal and home users. Optical waveguide devices owning the characteristics of miniaturization, high integration and huge communication transmission capacity have become a research hotspot. Erbium and ytterbium codoping chalcogenide glass optical waveguide amplifier (EYDWA) as an important communications network attracts all of us. Chalcogenide glass, due to its high nonlinear refractive index, ultrafast nonlinear response, ultra-low two-photon absorption and unique light-sensitive characteristics, has received the extensive research in recent years. In this paper ytterbium and erbium codoping chalcogenide glass optical waveguide amplifier has been investigated by systematically theoretical analysis, numerical simulation and parameters optimization.1.By high frequency electromagnetism module of ANSYS software, two-dimension|waveguide finite element model is founded.Guiding mode propagation constant and the field distribution are computed. Though analyzing the field distribution of two kind of waveguide with different size, multimode waveguide for film thickness1μm and single waveguide for film thickness0.4μm have been determined.2.Considering the cooperation up-conversion, cross-relaxation, excited state absorption, a comprehensive rate equations of Yb-Er codoped system energy level transition are founded.According to the chang of signal power and pump power along the active waveguide, propagation equation are given.3.Beacause the geometry size of two kinds of optical waveguide is different, two different ways are used to stimulate modes. Using FORTRAN software to program, coupling efficiency of optical fiber and multimode waveguide, excitation coefficients of each mode and normalized intensity of signal and pump light are calculated.4.Rate equation is combined with finite element field distribution propagation equations.Using Runge-Kutta multi-step technique, the gain of YEDAWA is solved, and the polarization characteristic is analyzed.5.Parameters are optimized in the simulation. Using the map ploting by the software of ORIGIN, we analyze the effect of cooperation up-conversion, excited state absorption and Yb-Er concentration ratio on inversion populations, and the relationship between signal power, pump power, doped concentration, waveguide length and gain.6. By calculating YEDAWA gain, considering of CU、CR、ESA, we get a gain of2.8dB/cm for multimode waveguide amplifier, and2.4dB/cm for single-mode waveguide amplifier.