Study Of Arrayed Waveguide Gratings Based On Thin-film-on-insulator Materials

As the global demand for information grows exponentially,thin-film integrated optical systems bring hope for breaking Moore’s Law.As an important optical device in optical communication networks,the arrayed waveguide grating(AWG)also needs to be miniaturized.The popular integrated optical material platforms in recent years,silicon-on-insulator(SOI)and lithium niobate-on-insulator(LNOI),play a key role in optimizing the size and performance of optical devices by virtue of their high refractive index contrast.Based on these two thin-film-on-insulator materials,theoretical and experimental studies on AWG are carried out in this paper.Firstly,on the basis of investigating the related research progress of AWG based on SOI and LNOI platform,the basic structure and working principle of arrayed waveguide grating are expounded,and the design process and performance index of AWG are summarized.Then,based on the SOI platform,an 8-channel AWG with the channel spacing of 1.6 nm is designed.After optimizing the performance of AWG,the size of the device is only 1.4×0.84mm~2.The experimental results show that the central wavelength of the AWG is 1552.3 nm,and the channel spacing is 1.56 nm.The insertion loss is 9.6 dB,the crosstalk between adjacent channels is about-10 dB,and the channel consistency is only 0.68 dB.Hereafter,an 8-channel AWG with the channel spacing of 1.6 nm is designed and fabricated on the LNOI platform based on a 300 nm-thick strip waveguide.After optimization of the design and fabrication process,the size of this AWG is reduced to 3.8×3.6 mm~2.The experimental results show that the center wavelength of the AWG is 1541 nm,the channel spacing is about 1.52 nm,the peak insertion loss of the center channel and the edge channel are16.04 dB and 16.31 dB,respectively,and the channel consistency is only 0.27 dB.Through theoretical and experimental studies on AWG based on two thin-film-on-insulator materials,this paper lays a good foundation for the future on-chip integration of wavelength division multiplexer with other optical devices.