Packaged, high-Q, microsphere-resonator-based add–drop filter

Abstract

In this Letter a packaged add-drop filter composed of a silica microsphere resonator and two fiber tapers is demonstrated theoretically and experimentally. A two-step fabrication process using an UV curable polymer is shown to stabilize the microsphere resonator with a diameter of 153 μm coupled to two tapered microfibers with diameters of 1.5 μm which are used as add and drop ports. A high loaded quality factor (Q-factor) of 0.9×105 and a free spectral range (FSR) of about 104 pm are obtained at around 1550 nm from the microsphere for the parallel coupling tapered fibers in the add-drop configuration. This device has a range of advantages, such as ease of fabrication, low-cost, and compatibility with traditional and commercial fiber systems.