1.5 μm spectral band laser power modulation multilayer graphene refractive index

Multilayer graphene refractive index (RI) modulation over laser power between 0.6 and 14.3 mW at 1500 nm to 1620 nm wavelength band is performed based on a half graphene cladding fiber Bragg grating (FBG), coming from an FBG, which half is cladding etched and coated with graphene, and another half of the FBG is remained. By measuring the wavelength difference between these two parts of the FBG, the temperature cross sensitivity can be removed. With the in-fiber laser power increase, RI of the multilayer graphene exhibits linearly increasing modulation process. The RI modulation can be deduced by the modulation efficiency of Bragg wavelength shift versus power. The modulation efficiency of different wavelength laser is slightly different, which is mainly due to the different interaction area between light field and coating graphene. The maximum modulation efficiency can get 59.3 pm/mW corresponding to 0.0545RIU (refractive index unit)/W RI modulation efficiency and 7.446 x 10(-4) RI increment of the multilayer graphene.