Arrayed Waveguide Grating Wavelength Division Multi/Demultiplexers Based On Boron-Germanium Co-doped Upper Cladding

Nowadays, upgrading telecommunication networks to increase their capacity is becoming increasingly important due to the rapid increase in network traffic. Wavelength division multiplexing (WDM) provides a new dimension for solving capacity and flexibility problems. Ever since its invention in 1980s, AWG as the backbone device of WDM is being studied around the world. The performance of the AWG is conducive to the improvement of network performance and lower costs. Through summarizing the technology of typical WDM devices, we find that silica arrayed waveguide grating device is a very good choice for developing WDM technology to get high performance and low-cost.Based on Silica AWG, this thesis is mainly to complete the following works:First the basic principles of array waveguide grating are described, and then we introduce the index of key performance and estimation methods. The overall design of AWG devices is also introduced.Then the fabrication process of integrated Silica waveguide devices is studied and reasonable parameters of process is obtained for realization of devices based on planar waveguide technology.In order to overcome the existing problems of planar waveguide fabrication, we propose a new Boron-Germanium Co-doped Upper Cladding process. Plasma enhanced chemical vapor deposition (PECVD) is commonly used for the deposition of silica waveguide layers. When the gaps between waveguides are small, voids are created during the deposition of the upper cladding. This letter presents a new process for filling the gaps of PECVD silica waveguides using boron-germanium co-doped upper-cladding and high-temperature annealing. Using appropriate doping concentrations as determined by processing gas flow rates, the gap was filled completely. By avoiding the use of toxic phosphine, the proposed method has potential advantages compared with the commonly used borophosphosilicate glass (BPSG) process.Finally, the Boron-Germanium Co-doped Upper Cladding process is used in the fabrication of two practical examples of cross-order AWG-Triplexer and 16-channel' Polarization-Compensation AWG. A compact arrayed waveguide grating triplexer with silica waveguides on silicon is designed, fabricated and characterized. Different cross-order designs, which utilize different diffraction orders to cover a large spectral range from 1310 to 1550nm, are analyzed in detail. B-Ge co-doped upper cladding is used to facilitate the gap-filling between the waveguides to reduce the loss and the polarization sensitivity. The measured spectra confirmed the operation principle of the cross-order AWG design, with channel wavelengths and passbands consistent with simulations.In this thesis, a new design method for eliminating the polarization dispersion of AWGs is presented. By utilizing the birefringence difference between the slab waveguides and the arrayed waveguides, a polarization insensitive AWG can be realized without requiring any additional fabrication step. Simulation and experimental results confirmed the feasibility of this technique. Meanwhile, the polarization dispersion of the AWG based on B-Ge co-doped upper cladding is not a serious problem and PDλis only 0.045nm due to rich-doped silica in the upper cladding.