Liquid-crystal space and wavelength routing switches

Two liquid-crystal based optical switching devices for application in a fiberoptic network are presented. They are the space-division fiberoptic routing switches and the dense-wavelength-division-multiplex (DWDM) routing switches. These two devices are the essential building blocks for constructing fiberoptic routing networks without using conventional opto-mechanical devices. The novel liquid-crystal fiberoptic routing switch demonstrated has similar performance specifications as opto-mechanical switches but with a much faster switching speed. An optical "robust" architecture incorporated within this switch design allows it to be operated over a broad spectral window and a wide temperature range, while maintaining an extremely low crosstalk, low insertion loss, low polarization dependent loss and low polarization mode dispersion. The innovative structure of the liquid-crystal wavelength routing switch integrates wavelength filtering and spatial routing functions into a compact device. The versatile filter design provides a prescribed wavelength transmission function and maintains low optical channel isolation. Again, the robust optical design is implemented to achieve excellent thermal stability on this wavelength switch.