| 摘要 |
In a digital optical switch which is based on the modeselectivity principle, made up of a passive section (A) containing a first optical wave guide (1) and a second optical wave guide (2) and a switching section (B) containing a third optical wave guide (3) and a fourth optical wave guide (4), both the required asymmetry and the bringing of the optical wave guides within or outside each other's interaction region are achieved with the aid of curves (K1, K2) in said optical wave guides. In the switching section (B) said asymmetry is switchable. Use is made of the effect that a curve results, in general, in a reduction of the propagation constant in the optical wave guide. Suitable curves are of circular-arc shape and sinusoidal. The switching section (B) may furthermore incorporate a short intermediate section (s-u) in which the optical wave guides (12, 13) run straight at a small mutual angle (.PHI.) in the event that the switchable asymmetry is in the first instance too small with a particular choice of material. The invention makes possible much shorter switches which have a greater packing density.
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