Tilted Bragg gratings in step-index polymer optical fiber

Abstract

We report the first slightly tilted Bragg gratings photo-inscription in polymer optical fiber (POF). For this, we make use of trans-4-stilbenemethanol-doped photosensitive step-index poly(methyl methacrylate) (PMMA) POFs. Tilted fiber Bragg gratings (TFBGs) are inscribed in the near-infrared wavelength range using the scanning phase mask technique with a tilted phase mask in the plane perpendicular to the laser beam direction. The transmitted amplitude spectrum evolution of a 3° TFBG is analyzed as a function of the surrounding refractive index. A maximum sensitivity close to 13 nm/RIU (refractive index unit) is obtained in the range 1.42-1.49.

Fast and stable gratings inscription in POFs made of different materials with pulsed 248 nm KrF laser

“…With this laser, the writing time in POFs was ranging from few to hundreds of minutes depending on the polymer material the fibers were made from, the inscription power, the structure of the fibers, and so on [8,19,21,22]. These inscription times can be significantly reduced by doping the fiber, which can be made with trans-4-stilbenemethanol (TS) that can also increase the grating reflectivity [28,29]. Benzyl dimethyl ketal (BDK) PMMA POFs also demonstrated inscription times as short as 4 minutes with a HeCd CW laser [30] and to 40 seconds with a femtosecond laser [31] or even to 1 pulse using a KrF pulsed laser [4].…”

Phase-Shifted Bragg Grating Inscription in PMMA Microstructured POF Using 248-nm UV Radiation

“…In recent years, the polymer optical fibe Bragg gratings (POFBGs) fabrication technology has been intensively established using uniform FBGs [16]- [19], tilted FBGs [20], chirped FBGs [21], and FBGbased Fabry-Perot interferometers [22]. Specifi material properties, such as low Young's modulus (about 3 GPa compared to 72 GPa for silica), a very large breaking strain, as well as biological compatibility, opens a variety of new applications unattainable for silica fibers In the published literature, one can fin studies reporting on applications of single FBGs in POFs as sensors of strain [23], acoustic waves [24], temperature [23], [25], humidity [25], accelerometer [26] or liquid level [27], [28].…”

Polymer optical fiber sensors in human life safety

“…In POF technology, the most widely used type in POF sensing applications is the uniform FBG [1,[6][7][8][9][10][11]13,17,24,[26][27][28][29][30][31][32]37,50]. However, recently some great papers showing TFBGs and CFBG in POF for sensing applications were reported [51,52,53].…”

“…These unique spectral features make possible a wealth of applications [54][55][56][57]. Xuehao Hu et al investigated the first TFBG photo-inscribed in PMMA POF for (bio)chemical sensing applications [51]. Fig.…”