Micro-structured fiber Bragg gratings. Part I: Spectral characteristics

Abstract In this paper, the authors present a detailed theoretical and numerical analysis of an in-fiber photonic device based on micro-structured fiber Bragg gratings for sensing and telecommunication applications. The investigated structure consists in a fiber Bragg grating with a localized stripping of the cladding layer. The thinning of the cladding layer changes the core propagation features and thus it induces a phase delay on the guided mode, leading to the formation of a defect state inside the original grating band-gap in agreement with the phase-shift grating theory. The behaviour of the defect state is ruled by three main parameters identified in the length and depth of the stripped region and the surrounding refractive index. This special characteristic leads to the possibility to realize a new class of active and passive photonic devices. In particular, here, the theoretical and numerical analysis of the spectral behaviour exhibited by the device and its dependence on the perturbation features have been carried out. Particular emphasis has been focused on the effect of the SRI on the spectral response, providing an exhaustive analysis of the potentiality of the device both for sensing and telecommunication applications. In addition, the investigation of standard uniform and strong fiber Bragg gratings has been carried out. Finally, the case of real devices realized by wet chemical etching in hydrofluoric acid solutions was analysed and a spectral equivalence was found to extend the design rules identified for the ideal case.

[1]  Benjamin J. Eggleton,et al.  Compact resonant integrated microfluidic refractometer , 2006 .

[2]  John E. Sipe,et al.  Long-period fiber gratings as band-rejection filters , 1995 .

[3]  Clinton Randy Giles,et al.  Lightwave applications of fiber Bragg gratings , 1997 .

[4]  Vincenzo Petruzzelli,et al.  Photonic band gap filter for wavelength division multiplexer. , 2003, Optics express.

[5]  Philippe Ferrari,et al.  Tunable bandpass microwave filters based on defect commandable photonic bandgap waveguides , 2003 .

[6]  F. Arregui,et al.  Fiber-optic multiple-wavelength filter based on one-dimensional photonic bandgap structures with defects , 2004, Journal of Lightwave Technology.

[7]  M. Monerie,et al.  Propagation in doubly clad single-mode fibers , 1982 .

[8]  A. Cusano,et al.  Refractive index sensor based on microstructured fiber Bragg grating , 2005, IEEE Photonics Technology Letters.

[9]  John A. Rogers,et al.  Digitally tunable microfluidic optical fiber devices , 2003 .

[10]  B. Eggleton,et al.  Microstructured optical fiber devices. , 2001, Optics express.

[11]  Jong-Hyun Lee,et al.  A micromachined in-plane tunable optical filter using the thermo-optic effect of crystalline silicon , 2003 .

[12]  B. E. Nelson,et al.  Use of a dielectric stack as a one-dimensional photonic crystal for wavelength demultiplexing by beam shifting. , 2000, Optics letters.

[13]  J. Rogers.  Tunable microfluidic optical fiber , 2002, Conference on Lasers and Electro-Optics, 2004. (CLEO)..

[14]  Ignacio Del Villar,et al.  Analysis of one-dimensional photonic band gap structures with a liquid crystal defect towards development of fiber-optic tunable wavelength filters. , 2003, Optics express.

[15]  Li Wei,et al.  Phase-shifted Bragg grating filters with symmetrical structures , 1997 .

[16]  P. Herman,et al.  Strong fiber Bragg grating fabrication by hybrid 157- and 248-nm laser exposure , 2002, IEEE Photonics Technology Letters.

[17]  M. Okano,et al.  A channel drop filter using a single defect in a 2-D photonic crystal slab-defect engineering with respect to polarization mode and ratio of emissions from upper and lower sides , 2003 .

[18]  O. Leminger,et al.  Phase-shifted Bragg-grating filters with improved transmission characteristics , 1995 .

[19]  G. Stewart.  Optical Waveguide Theory , 1983, Handbook of Laser Technology and Applications.

[20]  A. Cusano,et al.  Thinned fiber Bragg gratings as high sensitivity refractive index sensor , 2004, IEEE Photonics Technology Letters.

[21]  Shinpei Ogawa,et al.  Semiconductor three-dimensional and two-dimensional photonic crystals and devices , 2002 .

[22]  R. Kashyap.  Fiber Bragg Gratings , 1999 .

[23]  A. Evans,et al.  A new masking technology for deep glass etching and its microfluidic application , 2004 .

[24]  D. M. Atkin,et al.  Full 2-D photonic bandgaps in silica/air structures , 1995 .

[25]  Chongjun Jin,et al.  Demultiplexer using directly resonant tunneling between point defects and waveguides in a photonic crystal , 2002 .

[26]  Min Gu,et al.  Microfluidic tunable photonic band-gap device , 2004 .

[27]  Agostino Iadicicco,et al.  Microstructured fibre Bragg gratings: analysis and fabrication , 2005 .

[28]  John Canning,et al.  UV lamp hypersensitisation of hydrogen-loaded optical fibres. , 2003, Optics express.

[29]  H. Haus,et al.  Channel drop filters in photonic crystals. , 1998, Optics express.

[30]  Steven G. Johnson,et al.  Photonic Crystals: Molding the Flow of Light , 1995 .

[31]  I. Del Villar,et al.  Fiber-optic nanorefractometer based on one-dimensional photonic-bandgap structures with two defects , 2004, IEEE Transactions on Nanotechnology.

[32]  B. Benkelfat,et al.  An electro-optic modulation technique for direct and accurate measurement of birefringence , 2003 .