| 摘要 |
<p>Optical fibres are each retained in respective holders by which the ends of the fibres may be centered at a contact location. Each of the fibres is bent over a radius dependent on the light wavelength in its respective light coupling means for coupling light to the fibres. Light from a light source passes the contact location and is measured with the aid of a light detector and a measuring instrument. For each fibre the apparatus has a mode filter including a cylinder over which the fibre is bent half a turn. This cylinder has a radius which is greater than the cylinder radius in the light coupling means. A light signal has a basic mode with a symmetric energy distribution, which passes through the first mode filter, while higher order asymmetric modes are filtered out. A light signal in the second fibre has higher order modes generated at the contact location, these modes being filtered out in the second mode filter, so that a light signal with only basic modes actuates the detector. A splice with low signal attenuation may be obtained by only using the symmetric basic mode during detection of the fibre centering.</p> |
