The mode-spacing of the fiber Bragg grating Fabry-Perot (FBG F-P) cavity is calculated by using the effective cavity length which contains the effective length of the FBG.

• 利用包含光栅有效长度在内的有效腔长来计算光纤布拉格光栅法布里-珀罗腔的模式间隔。