Long-period gratings in wavelength-scale microfibers.

CO2 laser induced long period gratings in optical microfibers.

Long period gratings (LPGs) are fabricated by use of focused high frequency CO(2) laser pulses to periodically modify the transverse dimension of silica microfibers. A 20-period LPG with a 27 dB attenuation dip is realized in a microfiber with a diameter of approximately 6.3 microm. The resonant wavelength has a negative temperature coefficient and a high sensitivity to external refractive inde...

Fiber Bragg gratings in optical microfibers

Fabrication of strong long-period gratings in hydrogen-free fibers with 157-nm F2-laser radiation.

Long-period gratings were fabricated in standard telecommunication fiber (Corning SMF-28) by use of what is believed to be record short-wavelength light from a 157-nm F(2) laser. Strong loss peaks were formed without the need for enhancement techniques such as hydrogen loading. The magnitude of the attenuation peak was sensitive to the single-pulse laser fluence, decreasing with increasing puls...

TEMPERATURE CHARACTERISATION OF LONG PERIOD GRATINGS for SENSOR APPLICATIONS

Long period grating proposed as a sensor display sensitivity to ambient temperature variations. Therefore full temperature characterisation is essential. In this paper the temperature effects on the spectral profiles of two sets of long period gratings (LPGs) of different periods are investigated. The results obtained show that the shorter period LPGs were found to be less sensitive than the lo...

Analysis of optical response of long period fiber gratings to nm-thick thin-film coatings

We have theoretically and experimentally demonstrated that the resonant wavelength of long period fiber gratings (LPG) can be shifted by a large magnitude by coating with only a nm-thick thin-film that has a refractive index higher than that of the glass cladding. The resonant wavelength shift can result from either the variation of the thickness of the film and/or the variation of its refracti...