Experimental investigation and simulation of phase-shifted fiber Bragg gratings

This work reports the inscription and investigation of phase-shifted fiber Bragg gratings. A method for the inscription of such structures that makes it possible to vary the full width at half-maximum of the transmission notch in the reflection band within the range of 8–76 pm is proposed. The influence of the amplitude of the induced refractive index modulation and length of the formed structure on the studied parameter is investigated and analyzed. The results are presented as curves for data collected experimentally and theoretically. The investigation conducted in this study makes it possible to manufacture structures with known widths of the transmission notches, opening up a wide spectrum of possibilities to design optical elements based on such specific Bragg grating structures (e.g., fiber-optic sensors, tunable transmission filters, and demultiplexers).