Biofunctionalized tilted Fiber Bragg Gratings for label-free immunosensing.

We present a study aimed at developing a label-free optical fiber biosensor for detection and quantification of biomolecules in real-time. The biosensor based on a Tilted Fiber Bragg Grating (TFBG) transduces a binding event between the probe and target molecules into a change in the refractive index of the medium surrounding the fiber. This work describes the experimental results obtained with three methods for immobilizing biomolecular probes on a TFBG silica cladding surface.

Thermal wavelength stabilization of Bragg gratings photowritten in hole-filled microstructured optical fibers.

We demonstrate that the resonance wavelength of fiber Bragg gratings photowritten in the core of microstructured optical fibers can be efficiently stabilized versus temperature by inserting suitable refractive index materials with a negative thermal sensitivity into the holes. By these means, the effective index of the guided mode undergoes thermal variations which counterbalance the effect of the grating period thermal drift. The residual excursion of the resonance wavelength can be limited to less than +/- 10 pm over a 70 degrees C range of temperature into Microstructured Optical Fibers (MOFs) having realistic geometrical parameters, and using existing refractive index materials.

Three-hole microstructured optical fiber for efficient fiber Bragg grating refractometer.

We present a photosensitive three-hole microstructured optical fiber specifically designed to improve the refractive index sensitivity of a standard fiber Bragg grating (FBG) sensor photowritten in the suspended Ge-doped silica core. We describe the specific photowriting procedure used to realize gratings in such a fiber. We then determine their spectral sensitivity to the refractive index changes of material filling the holes surrounding the core.

Tilted Fiber Bragg Grating photowritten in microstructured optical fiber for improved refractive index measurement.

We report what we believe to be the first Tilted short-period Fiber Bragg Grating photowritten in a microstructured optical fiber for refractive index measurement. We investigate the spectral sensitivity of Tilted Fiber Bragg Grating to refractive index liquid inserted into the holes of a multimode microstructured fiber. We measure the wavelength shift of the first four modes experimentally observed when calibrated oils are inserted into the fiber holes, and thus we determine the refractive index resolution for each of these modes.

Apodized fiber Bragg gratings manufactured with the phase plate process.

We present a manufacturing method based on the dynamic use of phase plates to photowrite Bragg gratings. This process allows for control of the local value of the index modulation envelope in the grating. The application to apodized fiber Bragg gratings is discussed.