Abstract
We present results on the measurements of polarization dependent loss (PDL) of mechanically induced long-period fibre gratings. It is shown that a proper choice of the fabrication parameters leads to a considerable reduction of PDL values.

Abstract
In this article, we present detailed results on the fabrication and characterization of mechanically induced gratings produced by winding a string around a fiber/tube set. A comparison between the mechanical and arc-induced gratings is made, which allowed its to draw some conclusions on the formation mechanisms of the latter. The usefulness of mechanical gratings in research labs is discussed and two typical applications are. also presented. (C) 2008 Wiley Periodicals, Inc.

Abstract
The formation mechanisms and properties of arc-induced gratings are intrinsically related to the temperature attained by the fiber during arc exposure. In this work, we present further results oil the estimation of the fiber temperature based oil the use of electrically insulated thermocouples. Computer simulations show that under typical arc discharge conditions, the fiber reaches steady-state thermal equilibrium in less than half a second, having a peak temperature of about 1350 degrees C (C) 2008 Wiley Periodicals, Inc.

Abstract
We discuss the writing of arc-induced long-period fiber gratings to be used as optical filters in Er/Yb fiber lasers and for flattening the gain spectra of Er-doped fiber amplifiers. A new approach for the fabrication of filters with complex profiles is also presented. (c) 2008 Wiley Periodicals, Inc.

Abstract
The electric arc technique is used to apodize fiber Bragg gratings (FBGs). Arc discharges applied to the ends of the grating produce a smoothing of the refractive-index modulation profile reducing the sidelobes of the reflection spectrum at longer wavelengths. A sidelobe reduction of 17 dB was obtained. (c) 2007 Wiley Periodicals, Inc.

Abstract
The thermal behavior of long-period gratings arc-induced in B/Ge codoped fibers is presented. We also demonstrated the possibility to erase gratings written in Ge-doped and B/Ge codoped fibers through uniform exposure to UV-laser radiation. The gratings spectra were afterward recovered by thermal annealing. permanent thermally induced refractive index changes were found. (C) 2007 Wiley Periodicals, Inc.