By filling the liquid crystal (LC) in the air holes of a photonic crystal fiber (PCF) with 8 mm length, a compact multi-band thermal optical switch is proposed here including two important telecommunication band, i.e., 1265 to 1317 nm and 1508 to 1568 nm. Within the bandwidth, the extinction ratio can be as high as 30 dB. Under the combined action of the bandgap-guiding mechanism and the interference effect, a temperature change of only 1 °C after clearing temperature ( T_c ) of the LC induces multi-band thermal optical switch of the LC-filled PCF. It is also noted that the transmission spectrum of the LC-filled PCF is quite sensitive to the ambient temperature. The consequent thermal sensitive is 3.9 nm/°C, making it a very good candidate for monitoring the temperature herein.

中文翻译：

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向列液晶填充光子晶体光纤的多波段热光开关

通过在长度为8 mm的光子晶体光纤（PCF）的气孔中填充液晶（LC），在此提出了一种紧凑的多波段热光开关，该开关包括两个重要的电信频段，即1265至1317 nm和1508到1568 nm 在带宽内，消光比可以高达30 dB。在带隙引导机制和干扰效应的共同作用下，清除温度后温度仅变化1°C（ Ť _ç LC的）引起LC填充PCF的多波段热光开关。还应注意，填充LC的PCF的透射光谱对环境温度非常敏感。随之而来的热敏度为3.9 nm /°C，使其成为监测此处温度的很好的候选者。