Position tunable volume reflection gratings for narrowband filtering applications (FWHM <5 nm) in optical fibre systems

The authors report a significant improvement in the performance of position-tuned volume reflection gratings in dichromated gelatin for fibre-based applications in the 1200-1600 nm range. Full widths at half-maximum of less than 5 nm have been obtained over the whole tuning range, with high peak efficiencies for DCG films of 410 mu m thickness. These films are considerably thicker than have been reported elsewhere for IR or visible wavelength devices.