Low temperature sensitivity on-chip Fouriertransform spectrometer based on dual-layer Si_(3)N_(4)spiral waveguides  

作　　者：LIANGJUN LU HONGYI ZHANG XIN LI JIANPING CHEN LINJIE ZHOU 

机构地区：[1]State Key Laboratory of Advanced Optical Communication Systems and Networks,Shanghai Key Laboratory of Navigation and Location Services,Department of Electronic Engineering,Shanghai Jiao Tong University,Shanghai 200240,China [2]SJTU-Pinghu Institute of Intelligent Optoelectronics,Pinghu 314200,China

出　　处：《Photonics Research》2023年第4期591-599,共9页光子学研究（英文版）

基　　金：National Natural Science Foundation of China(62075128,62090052,62135010)。

摘　　要：On-chip Fourier-transform spectrometers(FTSs)based on Mach–Zehnder interferometer(MZI)arrays suffer from severe central wavelength and fringe contrast variation due to fabrication errors.Even though a calibration matrix can be employed to correctly retrieve the input spectra,environmental temperature variation greatly degrades the retrieving performance.In this paper,we devise a dual-layer Si_(3)N_(4) waveguide interferometer to reduce the temperature sensitivity.The beating of the even and odd supermodes in the dual-layer waveguide generates periodic intensity fluctuations in the spectrum.Since these two modes have similar modal profiles,their thermal sensitivity and propagation loss are relatively balanced,leading to a low temperature sensitivity and a high interference extinction ratio.We designed and fabricated a passive FTS based on a 32-channel dual-layer Si_(3)N_(4) waveguide array.Experimental results show that the temperature sensitivity is reduced to 10 pm/°C,which is almost half that of single-layer Si_(3)N_(4) MZI-based FTSs.With this chip,we accurately reconstructed various types of optical spectra,including single and two sparse laser lines,and broadband optical spectra.Our method can fit a wide wavelength range,which is a promising technology to improve the practical applications of on-chip FTSs.

关 键 词：waveguide INTERFEROMETER LAYER 

分 类 号：O43[机械工程—光学工程]