A Practical Approach to Synthesize Multi-channel Fiber Bragg Grating with Right-Angled Triangular Spectrum

A novel approach is proposed towards the design of fiber Bragg gratings with multi-channel right-angled triangular spectrum. Firstly, a single-channel grating is synthesized utilizing an adaptive quantum particle swarm optimization with the piecewise constant mutated factor. Meanwhile, the reflectivity spectrum with good linear edge for a short grating is obtained. Then, for its merits of easy fabrication, the superposition method is adopted to design multi-channel gratings with initial spectral distortion. Finally, this distortion is optimized by the method in the first step. It is shown that the design outcomes still retain the features of easy fabrication and short length. Such gratings would be useful as wavelength-interrogation devices with multiple physical parameters in optical sensor systems.