Very broad reflection bandwidth (44 nm) chirped fibre gratings and narrow bandpass filters produced by the use of an amplitude mask (original) (raw)

1994, Electronics Letters

Chirped gratings with very broad reflection bandwidths up to 44 nm and high reflectivity have been produced holographically in boron-codoped and standard telecommunications fibers which have been hydrogen-soaked. A 2 nm wide transmission band has been produced within the broad reflection band by use of an amplitude mask during grating exposure.

Reflections near 1030 nm from 1540 nm fibre Bragg gratings: Evidence of a complex refractive index structure

Optics Communications, 2005

Reflections at wavelengths other than the expected harmonics of phase-mask-written fibre Bragg gratings (FBGs) have been observed. It is argued that these are a consequence of the complex structure induced in the fibre core during fabrication. Various FBGs have been investigated, involving different formation regimes and fibre types, different writing wavelengths, exposure sources (e.g., pulsed and continuous wave) and different phase masks. The experiments showed that no specific observation could be attributed to a particular aspect of the fabrication process except the phase mask. The lack of higher diffraction order suppression of the phase mask is suggested as the origin of the complex structure in refractive index modulation that is induced within the fibre core, giving rise to more than one set of harmonic reflections that would be expected from a simple, single period grating.

Fabrication of high-reflectivity superimposed multiple-fiber Bragg gratings with unequal wavelength spacing

Optics Letters, 2002

We report the inscription of as many as 10 superimposed Bragg gratings of high reflectivity in a 25-mm segment of fiber. Using hydrogenated boron codoped and germanosilicate fibers, we inscribed 10 superimposed gratings with reflectivities above 80% and 6 superimposed gratings with reflectivities above 98%, respectively. The superimposed gratings had unequal wavelength spacing and were written over a 20-nm wavelength span in the region of 1530 nm. The inscription of each new grating caused an increase in the FWHM linewidth of the existing gratings, while their reflectivity was unaffected.

Simulation and experimental characterization of dual chirped long period fiber gratings

2010

We demonstrate a novel device consisting of two concatenated chirped long period fiber gratings (LPG) that exhibit multiple pass bands. Transmission spectra of single and dual chirped LPG were simulated theoretically and investigated experimentally show a qualitatively good match. The dual chirped LPGs with multiple pass bands in the transmission spectrum could find applications as WDM channel isolation filter.

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