紫外曝光法制备高掺锗光波导分束器及耦合器

Design and Fabrication of Heavy Germanium Loading Waveguide Splitters and Couplers by UV Exposure Method

通过优化氮氧化硅薄膜的制备，获得均匀平整、掺锗浓度高的氮氧化硅薄膜。在优化光波导耦合器设计、载氢、紫外曝光等过程的基础上，利用KrF准分子激光，在掺锗氮氧化硅平面光波导中制备出了单模条形波导以及波导型耦合器和分束器。紫外光照射后重掺锗（锗掺杂原子数分数约为20％）平面光波导芯区的折射率最大增加约1．03倍，形成的条形波导传输损耗为0．28～0．32dB／cm。实验表明紫外光曝光强度与掺锗氮氧化硅玻璃折射率的改变量是非线性的，折射率的变化可调整载氢压强和时间、紫外照射的光强度、材料掺锗浓度等参数来控制。

Uniform and heavily Ge-doped silicon oxy-nitride film is obtained by optimized fabrication of silicon oxy- nitride film. Based on an optimal design of waveguide coupler, hydrogen loading and ultraviolet （UV） irradiation intensity, single-mode channel waveguides and waveguide couplers, made from germanium-doped silicon oxy-nitride, are fabricated by an UV irradiation from a KrF excimer laser on a planar waveguide. The maximum index increase is up to 1.03 times for heavy Ge-loading （about 20 % atomic fraction） waveguide core after the UV irradiation, and the transmission loss of the UV-written channel waveguide is 0.28~0.32 dB/cm. Experimental results demonstrate that the index increase in the Ge-doped silicon oxy-nitride with UV irradiation intensity is not linear, and it can be controlled by changing the hydrogen loading pressure and time, UV intensity and Ge-loading level.