Patent ID: 6701046
Filing Date: 2004-03-02
Classification: G02B

Abstract:
Method for producing a fused coupler, comprising a polarization maintaining fibre and a standard fibre, characterized in that it comprises the following stages:reducing the cross section of the standard fibre in such a way as to obtain a propagation constant for the standard fibre which differs from a propagation constant of the polarization maintaining fibre by less than a predetermined quantity corresponding to a condition permitting coupling between the fibres; bringing the two fibres into contact with each other; tapering the two fibres together and fusing a portion of each fibre, in a region where the two fibres are in contact with each other, at a fusion temperature which is higher than a predetermined temperature, where this predetermined temperature is such as to provide an extinction ratio of at least 20 dB at the output of the polarization maintaining fibre in case of a linear polarization at the input of the polarization maintaining fibre.