Heat-and-pull rig for fiber taper fabrication

We describe a reproducible method of fabricating adiabatic tapers with 3-4 μm diameter. The method is based on a heat-and-pull rig, whereby a CO ₂ laser is continuously scanned across a length of fiber that is being pulled synchronously. Our system relies on a CO₂ mirror mounted on a geared stepper motor in order to scan the laser beam across the taper region. We show that this system offers a reliable alternative to more traditional rigs incorporating galvanometer scanners. We have routinely obtained transmission losses between 0.1 and 0.3 dB indicating the satisfactory production of adiabatic tapers. The operation of the rig is described in detail and an analysis on the produced tapers is provided. The flexibility of the rig is demonstrated by fabricating prolate dielectric microresonators using a microtapering technique. Such a rig is of interest to a range of fields that require tapered fiber fabrication such as microcavity-taper coupling, atom guiding along a tapered fiber, optical fiber sensing, and the fabrication of fused biconical tapered couplers.