Widely tunable filter based on coupling between a side-polished fiber and a tapered planar waveguide

We demonstrate a tunable filter with a wide tunable wavelength range (>300 nm) based on coupling between a side-polished fiber and a tapered planar waveguide (PWG). The thickness variation, due to sliding of the upper block, of taper PWG on the side-polished fiber region shifted the resonance wavelength of the coupler. Design and fabrication technique are presented.