基于不同液晶填充光子晶体光纤传输特性的研究

Transmission characteristics of photonic crystal fibers based on filling different kinds of liquid crystals

将5种不同折射率的液晶分别填入实芯光子晶体光纤的空气孔中,通过改变外场条件,研究其输出光谱的变化规律,并进行了理论模拟分析.结果表明:填充液晶后,输出光谱由全通变为多个波峰的带隙式;同时,液晶的折射率差值越大,其波峰位置越向长波长方向移动,且相对光强的对比度可以达到16 d B;温度由20°C上升到85°C时,波峰向短波长方向移动,最大调控范围可达41 nm;调节电压从0—250 V,输出光谱的相对光强变小,但波峰具有较好的稳定性;在室温下,波峰不随入射光偏振态的变化而变化.该液晶光子晶体光纤可应用于温控可调谐滤波器或电控衰减器.

The transmission characteristics of full-filled photonic liquid crystal fibers （PLCFs） which are filled with five kinds of liquid crystals （LCs） are experimentally studied and theoretically analyzed. The influences of temperature and external electric field on the transmission characteristics of PLCFs are also discussed in this paper. The transmission spectra of PLCFs show obvious bandgaps, and the number and the central wavelengths of the bandgaps depend on the average value of the refractive indices of LCs. By changing the temperature from 20℃ to 80℃, a blue shift in the bandgap is observed, and the maximum tuning range of the bandgap is 41 nm. Then, with the voltage turning from 0 V to 250 V, the output power of the transmission spectrum decreases, while the central wavelength of the bandgap is almost unchanged. Finally, the transmission spectrum keeps a good stability, even if the polarization state of the input light changes.