Thermally tunable bragg grating filters for wavelength-multiplexed systems

Abstract

In this contribution we compare the thermal tuning capabilities of two type I gratings, considering an unloaded and a hydrogen-loaded fiber, and a type IIa grating. We further study their responses stability with temperature, analyzing their potential as optical filters in wavelength division multiplexing systems. We conclude that all of them have similar tuning efficiencies, however, as the temperature is changed, the type I grating written in the unloaded fiber presents much higher variations on its reflectivity, bandwidth and group delay than the other two cases, misadvising its utilization as thermo-tunable optical filter for wavelength-multiplexed systems. The best tuning range/filter response variation balance is achieved for type IIa gratings.