Research Of Array Waveguide Grating At 2 ?m Wavelength Band

2?m wavelength band optical communication has attracted more and more attention in recent years.The gain spectrum of thulium-doped fiber amplifier is wider,and the photonic bandgap fiber(PBF)has a lower theoretical attenuation value(0.1 d B/km).These advantages help to solve the problem of large data traffic and limited spectral resources.Dense wavelength division multiplexing(DWDM)technology is the first choice to solve large-capacity information transmission in optical fiber communication.Array Waveguide Grating(AWG)is the key component of DWDM system.However,the the research of 2?m wavelength band AWG is still in its infancy,there is lots of room for improvement in performance,such as device loss,crosstalk,size,compatibility with CMOS,etc.Therefore,the thorough investigation is needed about the AWG of 2?m wavelength band.In this work,on-chip AWG has been researched suitable for DWDM technology at 2?m wavelength band.A brief description of the development on-chip AWG is shown,and the basic principles of the AWG are introduced,including the determination of various parameters and the indicators for assessing the performance of the AWG.The design and optimization of high-performance AWG are mainly based on silicon and silicon nitride platform,which is compatible with CMOS.The main factors affecting device performance are discussed,and the different waveguide gap distances are simulated and optimized.For the silicon AWG,the results show that the minimum insertion loss is 2.57 d B and the channel crosstalk is-20.43 d B.The final size of the device is about 1400×860?m~2.The design of 2?m wavelength band AWG which based on the silicon nitride material platform shows the minimum crosstalk is 1.68 d B,channel crosstalk is about-24.62d B,and the final device size is 3×2.5 mm~2.The AWG designs of both material platform all demonstrate better device performance and smaller device size.In addition,the grating couplers of two materials are designed aiming at the coupling problem between fiber and integrated optical waveguide at 2?m wavelength band.The grating couplers are designed respectively with waveguide thickness of 220 nm and 340 nm based on the silicon platform.The chirped grating achieved 31%coupling efficiency compared with the uniform periodic grating,and the coupling efficiency of shallow etching chirped grating is 52.4%.Based on silicon nitride platform,a fully etched grating coupler with uniform period is realized,and the coupling efficiency can reach 35.4%.