Virtual long-period gratings

Long Period Fibre Gratings

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 ...

Multiplexed long period gratings with differential interrogation

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...

Polarization-dependent loss and birefringence in long-period fiber gratings.

Widely used descriptions and relationships for birefringence and polarization-dependent loss (PDL), developed primarily for ultraviolet-induced long-period fiber gratings (LPFGs) written in optical fiber, can be invalid for other types of LPFG. The understanding of PDL is expanded to include LPFGs with birefringence in the core only, in the cladding only, and in both the core and the cladding. ...