Dai Daoxin, Wang Zhi, Bauters Jared F, Tien M-C, Heck Martijn J R, Blumenthal Daniel J, Bowers John E
Department of Electrical and Computer Engineering, University of California, Santa Barbara, CA 93106, USA.
Opt Express. 2011 Jul 18;19(15):14130-6. doi: 10.1364/OE.19.014130.
A 16-channel 200 GHz arrayed-waveguide grating (AWG) (de)-multiplexer is demonstrated experimentally by utilizing Si3N4 buried optical waveguides, which have 50 nm-thick Si3N4 cores and a 15 μm-thick SiO2 cladding. The structure with an ultra-thin core layer helps to reduce the scattering due to the sidewall roughness and consequently shows very low loss of about 0.4~0.8 dB/m. When using this type of optical waveguide for an AWG (de)multiplexer, there is no problem associated with gap refill using the upper-cladding material even when choosing a small (e.g., 1.0 μm) gap between adjacent arrayed waveguides, which helps to reduce the transition loss between the FPR (free-propagation region) and the arrayed waveguides. Therefore, the demonstrated AWG (de)multiplexer based on the present Si3N4 buried optical waveguides has a low on-chip loss. The fabricated AWG (de)multiplexer is characterized in two wavelength ranges around 1310 nm and 1550 nm, respectively. It shows that the crosstalk from adjacent and non-adjacent channels are about -30 dB, and -40 dB, respectively, at the wavelength range of 1310 nm. The Si3N4 AWG (de)multiplexer has a temperature dependence of about 0.011 nm/°C, which is close to that of a pure SiO2 AWG device.
通过利用具有50纳米厚Si3N4纤芯和15微米厚SiO2包层的Si3N4掩埋光波导，实验演示了一种16通道200吉赫兹阵列波导光栅（AWG）解复用器。具有超薄纤芯层的结构有助于减少由于侧壁粗糙度引起的散射，因此显示出非常低的约0.4至0.8分贝/米的损耗。当将这种类型的光波导用于AWG解复用器时，即使在相邻阵列波导之间选择小的（例如1.0微米）间隙，使用上包层材料进行间隙填充也没有问题，这有助于减少自由传播区域（FPR）和阵列波导之间的过渡损耗。因此，基于当前Si3N4掩埋光波导演示的AWG解复用器具有低片上损耗。所制造的AWG解复用器分别在1310纳米和1550纳米附近的两个波长范围内进行了表征。结果表明，在1310纳米波长范围内，相邻通道和非相邻通道的串扰分别约为-30分贝和-40分贝。Si3N4 AWG解复用器的温度依赖性约为0.011纳米/°C，这与纯SiO2 AWG器件的温度依赖性相近。
