Study Of Arrayed Waveguide Grating Multiplexer With Beam Propagation Method

The single channel transmission capacity of existing optical fiber network has been gradually filled with rapid growth of modern communications capacity. It is an effective way to resolve this problem by adopting dense wavelength-division multiplexing (DWDM) technology. And the application of dense wavelength-division multiplexing technology must depend on the development of all kinds of wavelength-division multiplexing devices. Among these devices, arrayed waveguide grating (AWG) with less power loss, low crosstalk and multiplexing/de-multiplexing function is regarded as the best choice for DWDM optical network. As it is mentioned above, it is worthwhile for optical communications to study arrayed waveguide grating multiplexer.For making the performance index of AWG designed reach the requirement of DWDM system, it is necessary to simulate AWG accurately with computer. This paper, firstly, introduces the development of beam propagation method (BPM), and on the basis of this introduction, several algorithms which come from combination of BPM and different boundary conditions have been studied and simplified. After analyzing some waveguide unit devices with these algorithms, it can be concluded that the simplified algorithms is effective. Secondly, this paper introduces the basic theory of waveguide and effective-index method (EIM), and then the configuration parameters and single-mode propagation condition of rib waveguide have been analyzed with effective-index method. At last, a simplified computation modal for AWG based on BPM is brought forward. And the local structure of AWG such as taper waveguide is investigated and optimized with this modal and effective-index method. It is concluded by computing and analyzing that lower insert power loss and flat spectral response can be achieved for AWG with optimized structure. Consequently, some performance parameters of AWG have been improved.