Analysis On The Characteristic Of TE₁Mode Field And Diffraction Far-field Of Planar Optical Waveguide

The transmission characteristics of the optical waveguide mode field are the theoretical basis of the design and optimization of the integrated optical devices. This paper focuses on the transmission characteristics of TE1mode of the planar optical waveguide and multi-quantum well (MQW) optical waveguide.The relationship between the M2factor of TE1mode and the normalized frequency is given, an fitting expression for M2factor as function of normalized frequency is suggested, the relative error caused by fitting is analyzed to explain the accuracy of the fitting function. On the condition of the M2factor of TE1mode is near to the Hermite-Gaussian beam, the Hermite-Gaussian approximation for TE1mode field is suggested and the matching efficiency between them is good, the relationship between the equivalent mode field half-width and normalized frequency is analyzed.Taking the GaAs/GaAlAs MQW optical waveguide as an example, the Hermite-Gaussian approximation for the far-field diffraction of TE1mode of MQW planar waveguide is taken and the matching efficiency between them are analyzed when the equivalent divergence half-angle in the Hermite-Gaussian approximation are different. Further, a compound exponential function is employed to fit the curve of the equivalent divergence half-angle versus the number of potential well layers and the relative error caused by fitting is analyzed to explain the accuracy of the fitting function.The distribution of the diffraction light intensity in the slow axis is given and the divergence angle in the slow axis shows in the diagram, the value of the divergence half-angle based on the defined of the second-order moments is calculated.