Byanalyzingandcomputing,accordingtothewavetheoryofplanaropticalwaveguideattenuation,anewopinionisputforward.Aseriesoftransmissionatteenuationwithwaveguidefilm-thicknessaregivenanditillustratesthatopticaltransmissionisnotcarryingoutefficientlywithinsomewaveguidefilm-thickness.