Title :
Bragg gratings with efficient and wavelength-selective fiber out-coupling
Author :
Fonjallaz, Pierre-Yves ; Limberger, Hans Georg ; Salathé, René Paul
Author_Institution :
Lab. of Photonics & Microwave Eng., R. Inst. of Technol., Kista, Sweden
fDate :
2/1/1997 12:00:00 AM
Abstract :
A new type of out-coupling Bragg grating has been fabricated in a standard depressed-cladding telecommunication fiber (3% Ge). In addition to the usual Bragg reflection, a narrow shorter wavelength-band is coupled out of the core guide. High out-coupling efficiency, more than 50%, and high spectral selectivity, 3 dB bandwidths as small as 0.4 mm, have simultaneously been achieved. The performances of such outcoupling elements are increased because of strong variations of the index change perpendicularly to the fiber axis. These are due to the fact that the gratings are narrower than the fiber core diameter. Based on the same principle, enhancement of the out-coupling efficiency is also obtained for gratings fabricated in fibers having a triangular core index profile
Keywords :
diffraction gratings; optical fibre cladding; optical fibre communication; optical fibre couplers; optical fibre fabrication; optical fibre filters; optical fibre losses; wavelength division multiplexing; 50 percent; Bragg gratings; Bragg reflection; SiO2-GeO2; core guide; fiber axis; fiber core diameter; high out-coupling efficiency; high spectral selectivity; index change; narrow shorter wavelength-band; optical fibre grating fabrication; out-coupling Bragg grating; out-coupling efficiency; standard depressed-cladding telecommunication fiber; triangular core index profile; wavelength-selective fiber out-coupling; Bandwidth; Bragg gratings; Fiber gratings; Interference; Optical filters; Optical losses; Optical reflection; Optical refraction; Optical variables control; Resonance;
Journal_Title :
Lightwave Technology, Journal of
