Experimental Analyses of Confined Thermal Effect on Chirped Fiber Bragg Grating

Chirped fiber Bragg gratings (C-FBGs) have found various important applications in the field of optical communication and sensing. These applications manipulated the distinctive refractive index structures, wherein its spectral response is modifiable by variation of its local physical property. This paper specifically analyzes the effect of localized thermal effect on C-FBG using a micro-size heating element to achieve confined heating. The results reveal that localized thermal effect will produce a phase-shift dip in the spectrum, whose depth, linewidth and center wavelength are correlated to the magnitude and position of the applied heat. This knowledge unveils the possibility of elastic spectral shaping of C-FBG, which will allow it to further find new applications.