The electrically tunable band-pass filter in the visible light region is demonstrated by the liquid-crystal infiltrated waveguide formed by the distributed Bragg reflectors with the length of 3 mm. As the white light source is launched in the waveguide, by applying the external voltages from 0 to 30 V(rms), the dynamic control of filter characteristics can be achieved to tune the color of the output light from white light to red, yellow or green. The intensity of the output light can also be attenuated by applying the voltage. The 25 dB attenuation can be achieved as the applied voltage is as low as 9 V(rms). (C) 2011 Optical Society of America
