| Abstract: | In a long period fiber grating(LPFG), the forward-propagating guided mode in the core is coupled to a number of co-propagating lossy cladding modes at resonance wavelengths. Sensitivity of resonance wavelength against temperature, axial strain, and external refractive index is modeled in this paper. Schemes for temperature compensation and enhanced wavelength tuning of LPFG are proposed and analyzed. Experiments show accordant results with simulations. Temperature coefficient of the LPFG compensated by means of axial strain is below 1.8 nm/100℃. For the LPFG with polymer recoating layer, the enhanced tuning range is more than 70 nm. |
