The bending characteristics of the long period fiber grating (LPFG) induced by high-frequency CO2 laser pulses in a bend insensitive fiber is reported. The experimental results show that the peak resonant amplitude of the LPFG written in a bend insensitive fiber has a higher sensitivity than that written in a standard telecommunication fiber. Furthermore, LPFG has different bending characteristics at circular orientation, i.e. the peak resonant amplitude of the LPFG is the most sensitive to bending but the resonant wavelength is insensitive at some circular orientations. Based on this finding, a gain equalizer is proposed to flat the gain of an erbium-doped fiber amplifier (EDFA) by bending directly. Such a system is shown to be a practical and simple approach to realize gain flattening of an EDFA with high precision for gain control.