Transmission Characteristics of Periodically Microridged Long-Period Fiber Grating Based on a Photonic Crystal Fiber

We propose the fabrication of the micro-ridge long-period fiber grating (MRLLPFG) by using both a wet etching and a periodic polymer coating methods. In addition, the PCF, for the first time to our knowledge, is exploited to fabricate the MRLPFGs. The transmission characteristics of the PCF-based MMRLPFG are measured. As the applied strain increases, two peak depths of the PCF-based MRLPFGs are changed because of the photoelastic effect. However, the resonant wavelengths are not shifted by varying strain. It means that the proposed PCF-based MRLPFGs are very useful for the application to strain sensors.