Long-period gratings in wavelength-scale microfibers

Long-period gratings in wavelength-scale microfibers.

We report the fabrication of long-period gratings (LPGs) in wavelength-scale microfibers with diameters from 1.5 to 3 microm. The LPGs were fabricated by use of a femtosecond IR laser to periodically modify the surface of the fibers. These LPGs have grating periods of a few tens of micrometers, much smaller than those in conventional optical fibers. A compact 10-period LPG with a device length ...

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...

Long Period Fibre Gratings

Talbot images of wavelength-scale amplitude gratings.

By means of experiment and simulation, we achieve unprecedented insights into the formation of Talbot images to be observed in transmission for light diffracted at wavelength-scale amplitude gratings. Emphasis is put on disclosing the impact and the interplay of various diffraction orders to the formation of Talbot images. They can be manipulated by selective filtering in the Fourier plane. Exp...

Sensitivity Enhancement in Low Cutoff Wavelength Long-Period Fiber Gratings by Cladding Diameter Reduction

The diameter of long-period fiber gratings (LPFGs) fabricated in optical fibers with a low cutoff wavelength was be reduced by hydrofluoric acid etching, enhancing the sensitivity to refractive index by more than a factor of 3, to 2611 nm/refractive index unit in the range from 1.333 to 1.4278. The grating period selected for the LPFGs allowed access to the dispersion turning point at wavelengt...