Crosstalk reduction by wavelength assignment

One common theme in designing optical switches is crosstalk reduction. Although this is a device level problem, it can also be solved at the system level. One approach is to use more switching elements. This is the so called "space approach". In the paper we show how to take advantage of the multiple-wavelength characteristic of a WDM signal to reduce crosstalk without adding more switching elements. Although we use directional-coupler photonic switching technologies for our discussion, the principle can be used for any photonic switching technology