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Multi-Edge-Written Long-Period Fiber Gratings with Low PDL by Using High-frequency CO2 Laser Pulses

A novel long-period fiber grating (LPFG) with low polarization dependent loss (PDL), for the first time to our knowledge, is fabricated by using a multi-edge exposure method with high frequency CO2 laser pulses in this paper. The experimental results show that the PDL of a triple-edge-written LPFG with apeak amplitude of-16.5dB can be as low as 0.18dB. These novel LPFGs can find important applications in optical communications and sensing.