Optical-fiber variable-attenuator arrays using polymer-network liquid crystal

This paper describes compact variable optical attenuator arrays made by using fiber splicers and polymer-network liquid crystal. Fibers are inserted into the splicers and the gaps between the ends of the fibers are filled with the polymer-network liquid crystal. The residual loss for each array element is low (about 0.8 dB), the attenuation of 1.55-μm light is about 8 dB and the driving voltage is 20 V/sub rms/. The polarization dependence is <2 dB. The power consumption is also very low (30 nW/ch). They are used for channel power equalizers for WDM systems.