Tunable microfluidic optical fiber gratings

We demonstrate periodic refractive index gratings in optical waveguides formed by microfluidic plugs that are infused into the airholes of a microstructured optical fibers. The periodic microfluidic plugs, created in the cladding, cause resonant coupling between copropagating optical fiber modes, which results in wavelength-dependent attenuation. We also demonstrate the ability to tune the resonant wavelength by compressing the microfluidic structure. These microfluidic resonant structures provide an alternative method for creating and tuning long-period gratings in optical fibers. This also represents an example of a resonant microfluidic structure and establishes potential strategies for enhanced tunable photonic crystal devices. (C) 2003 American Institute of Physics.