Multimode switches - switching by direct fiber movement

The best way for the switching optical fibers is the direct movement of the optical fibers with respect to each other. Piezoelectric actuators are ideal candidates for this purpose due to their typical movement ranges and actuation speed. In order to exclude the influences of hysteresis and creep on the accuracy of such a switch, the actuator end positions can be fixed by special stopping configurations. In the case of multimode fibers, the required accuracy (10 microns or more depending on the fiber core diameter) can be achieved by different approaches of precision engineering. For singlemode fibers, however, this approach is not very appropriate. Optical fiber switches using direct piezoelectrical movement of fiber ends have several advantages over alternative approaches with intermediate optics (for example SELFOC collimators): • High switching speed. • No influence of aberrations of intermediate optics • • No additional wavelength dependent loss introduced by the switch! High repeatability for cases where there is a combination with stopping configurations The latter point is of particular interest for spectroscopic and sensing applications. This type of switch can even be used in the UV region. Output fibers Input fiber Stopping p arts Piezoelectrical movement