Author,Title,Journal,ISSN,Publisher,Date,Volume,Number,Page,URL,URL(DOI) Yasuo Kokubun and Shuichi Tamura,Precise formula for calculating spot size in optical waveguides and its accuracy,Electronics and Communications in Japan (Part II: Electronics),8756-663X,Wiley,1994-10,77,10,1-12,https://cir.nii.ac.jp/crid/1361978698484407680,https://doi.org/10.1002/ecjb.4420771001