Low-loss Y-coupler for multimode single fibres

Abstract
A technique for making low-loss 3dB Y-couplers in multimode single fibres was developed and evaluated. The couplers were obtained by the fusion of two optical fibres by means of a neated Kantal wire. A set of fifty samples using a Pilkington step-index fibre showed an average excess insertion loss of about 0.7dB.