Asymmetric T-couplers for fibre optic data buses

A new type of T-coupler, a so-called asymmetric coupler, in which fibres having different core diameters are used has been realised. This technique can lead to a significant reduction in the input coupling losses between input terminals and transmission fibre. For a moderate number of terminals, the losses of a T-bus with asymmetric couplers are comparable to those of a star bus.