METHOD FOR MANUFACTURING LONG PERIOD FIBER GRATING FOR REDUCING LOSS OF POLARITY DEPENDENCY

摘要

PURPOSE: A method for manufacturing a long period fiber grating is provided to reduce PDL(Polarity Dependency Loss) by making refraction index distribution symmetric. CONSTITUTION: In a method of manufacturing a long period fiber grating, in step one(100), a long period grating is grated on an experimental optical fiber having the same characteristic as the optical fiber to be used for the long period fiber grating. In step two(200), The optimal output and projecting time of a UV laser are searched to make refraction index distribution uniform. In step three(300), The output value of the UV laser is set as the searched optimal output value. In step four(400), The UV laser projects the UV light on the fiber during the optimal projecting time to form the long period fiber grating.