As the deployment of wavelength division multiplexing (WDM) transmission facilities speeds up, it is a natural step to design a WDM crossconnect to route the WDM traffic. One of the switching devices that can pass WDM signals is the electro-optical directional coupler. However, directional couplers, as a photonic switching device, suffer from an intrinsic problem: crosstalk. How to remove the crosstalk at the system level has been an active research topic....[ Read more ]

As the deployment of wavelength division multiplexing (WDM) transmission facilities speeds up, it is a natural step to design a WDM crossconnect to route the WDM traffic. One of the switching devices that can pass WDM signals is the electro-optical directional coupler. However, directional couplers, as a photonic switching device, suffer from an intrinsic problem: crosstalk. How to remove the crosstalk at the system level has been an active research topic.

Past results have shown that by using more couplers, crosstalk can be reduced to an insignificant level. This is referred to as the space dilation approach. However, with WDM signals, we showed in this research that most of the additional hardware required by the space dilation approach is not needed. Crosstalk can be removed by taking advantage of the multiple-wavelength nature of signals. This is referred to as the wavelength dilation approach.