The advantages of using liquid-crystal modulators for optical signal switching have been demonstrated [1,2]. Liquid-crystal modulators utilize polarization manipulation without moving mechanical structures to route optical signals. This provides reliability of solid-state devices. Liquid-crystal cells require low control voltages and currents. Therefore, they consume less power than optomechanical switches do. Liquid-crystal material has low absorption in the infrared wavelengths. So the switches could have low insertion losses in the C and L bands. Furthermore, the insertion losses over a wide spectral range could be uniform with proper coating. Since liquid-crystal modulators manipulate optical polarizations to achieve two switching statuses, one can utilize the known polarization states in the optical paths to minimize polarization-dependent losses. These advantages make the liquid-crystal switches an attractive option for all-optical switching in reconfigurable WDM (wavelength-division-multiplexing) networks.
© 2001 Optical Society of AmericaPDF Article