Polarization-isolated electrical modulation of an etched long-period fiber grating with an outer liquid-crystal cladding

An etched long-period fiber grating with an outer liquid-crystal cladding capable of polarization-isolated electrical modulation, is de- scribed. A 5-dB transmission-dip modulation with 4-dB polarization iso- lation can be obtained at 225 V. The reduction in fiber diameter by a chemical etching process leads to an improvement in the long-range ordering of liquid-crystal molecules and a reduction in the controlling voltage. In addition, the experimental results are supported by numerical simulation.