Numerical Analysis of Thermal Dependence of the Spectral Response of Polymer Optical Fiber Bragg Gratings

Abstract

The thermal dependence of the spectral response (i.e. transmission, reflection and time delay (τr) responses) ofuniform polymer optical fiber (POF) Bragg gratings has been investigated. In addition to the temperaturedependence, the effects of grating strength (kLg) and fiber index modulation (∆n) have been investigated. Besideshigh capability of tunable wavelength due to the unique large and negative thermo-optic coefficient of POF, thespectral response for POF Bragg gratings show high stability and larger spectrum bandwidth with temperaturevariation compare with the silica optical fiber (SOF) Bragg gratings, especially with the increase of the kLg value. Itwas found that by increasing kLg, the peak reflectance value increases and the bandwidth of the Bragg reflectorbecome narrower. Also it’s shown by increasing the kLg value, τr deceasing significantly and reach its minimumvalue at the designed wavelength (λB). Furthermore, the τr for POF Bragg gratings is less than that for SOF Bragggratings at the same value of kLg. Also it’s found that the peak reflectivity value increases to around 60% when the∆n value increases from 1ˣ10-4 to 5ˣ10-4.