Polymer ring resonator made by two-photon polymerization and vertically coupled to a side-polished optical fiber

摘要

We have developed a novel approach for fabricating and testing optical ring resonators. Using a sidepolishedrnoptical fiber and fabricating a ring waveguide directly over its core, an efficient and passive signalrnfilter in the 1.55 um telecommunication band is created. A standard single mode optical fiber isrnpermanently secured in an arcing groove in quartz and is side polished proximally to its core. The ringrnresonator is fabricated using two-photon initiated free-radical polymerization of tri-functional acrylate onrnlow-index quartz substrate with a 100 femtosecond pulsed Ti/sapphire laser. The quartz substrate isrninverted and vacuum mounted to an X-Y-Z stage so that the polymer ring waveguide can be positionedrndirectly above the core of the fiber forming a vertically coupled ring resonator. Our technique allows infiniternvariation of the width, height, diameter and location (therefore the coupling strength between the fiber andrnthe ring) of the ring resonator waveguide. This approach enables resonators to be fabricated, tested andrnsubsequently removed multiple times on the same side-polished fiber, refining both the ring resonatorrngeometry and materials. Because it is a fiber-based device, it possesses negligibly low optical insertion lossrnand can be used for fixed and tunable wavelength filters, intensity modulators, and fiber-optic sensors. Bothrntheoretical analysis and experimental data will be presented.