Fibre-optic de-multiplexing coupling - is dimensioned such that longest arriving wavelength passes into next coupled optic fibre conductor

摘要

The optical coupling assembly, such as may be used for de-multiplexing, comprises a coupling (I,II) in which some of the light energy arriving in a first fibre conductor (1) passes into one or more second conductors (2,6). Upstream of the coupling area (K1,2; K1,6) the conductor (1) is curved (R1; R2) such that energy passes from the core into the mantel and from there into the core of the next conductor (2;6). The refractive index of the conductor (1) mantle is equal to or smaller than that of the next conductor (2;6) core. Where the conductor (1) carries more than one wavelength (lambda 1, 2,3), the coupling (I;II) is dimensioned such that the longest wavelength (lambda 3;2) passes into the next conductor (2;6).