Tilted Fiber Bragg Grating Inscription in Boron Co-Doped Photosensitive Optical Fiber Using 266 nm Solid State Laser Pulses

In the last decade, tilted fiber Bragg gratings (TFBGs) have received a lot of research attention due to their unique ability for detection of bending and surrounding refractive index (SRI). Meanwhile, fabrication of TFBGs normally requires fiber pre-hydrogenation and expensive laser systems, such as excimer laser at 193 nm or femtosecond lasers. In this work, we report the first TFBG inscriptions in Boron co-doping fibers (PS1250/1500, FIBERCORE) using low cost 266 nm solid state pulsed laser and scanning phase mask lithography technique. By using this inscription set-up, gratings with tilt angles from 2° to 10° are fabricated. Influences (pulse repetition rate and scanning speed) on the grating quality and spectral performances are discussed. Furthermore, evolution of spectra during the inscription of the 10° TFBG is illustrated showing uniform growths of both the core and cladding modes. In addition to the TFBG fabrication, temperature, bending and SRI measurement are conducted. Because the core mode is restricted to propagate in the fiber core, TFBGs could automatically provide temperature compensation. The ease of TFBG fabrication and the capability of intrinsic temperature self-compensation pave the way to their potentially promising applications in curvature and refractometric measurement.