Research On Multi-channel Arrayed Waveguide Grating

Upgrading telecommunication networks to increase their capacity and speed is becoming increasingly important due to the rapid increase in network traffic caused by multimedia communications. The traditional communication technologies and devices could not fulfill the demands. Arrayed waveguide grating(AWG), which is one of the key devices in dense wavelength division multiplexing(DWDM) systems, provides a feasible solution. Nowadays, AWG with the advantages such as much more signal channels, narrow channel spacing, low insertion loss, low crosstalk and flattened spectral response, plays an increasingly important role in optical fiber communication.First of all, the optical waveguide theories about AWG were researched. The structure of slab waveguide and rectangular waveguide were introduced, and their electromagnetic field distribution was discussed. Marcatili’s method and effective index method(EIM) were described briefly to analyze the rectangular waveguide. Then the principles as well as characteristic parameters of AWG were analyzed, and some methods to improve the performance were discussed. A 1×8 AWG demultiplexer with 1.6 nm-spacing was designed, and the connection among the key characteristic parameters, such as the number of wavelength channels, the core size, effective index, waveguide separation and the number of arrayed waveguides, were researched. A method of obtaining uniform output characteristics was presented in this thesis, and then the 1×8 AWG was simulated by RSoft BeamProp which based on finite difference beam propagation method(FD-BPM). The 1×8 AWG was fabricated by the ZPU UV curable polymer materials, which produced by Korea ChemOptics Company, and tested later. Finally, a 1×41 dense AWG demultiplexer with 0.4 nm-spacing was designed and simulated on the basis of above research. The simulation results show that, the technique used in the design process leads to low insertion loss and uniform output characteristics. The insertion loss of the outer output channel decreases to-2.9dB, the channel insertion loss uniformity decreases to 1.3 dB, the adjacent channel crosstalk was limited to around-25 dB, and the non-adjacent channel crosstalk was limited to around-40 dB.