Erbium-doped fiber splicing and splice loss estimation

Erbium-doped fibers, deployed in erbium-doped fiber amplifiers (EDFA), often have small mode diameters (about 4-6 μm). If these fibers were to be abruptly interfaced with larger mode field diameter (7.5-10.5 μm) dispersion-shifted or conventional fibers, unacceptably large transmission loss penalties would be incurred. However, since the diffusion speed of most erbium fiber designs is higher than other fibers, a special real-time control (RTC) splicing technique is developed based on an image processing and a synamic splice loss estimation procedure in order to assure optimum thermal diffusion of the fiber core dopants, thereby creating a tapered transition region between the mating fibers, resulting in fiber splices that have consistently low losses (<0.1 dB) and high strength (>200 kpsi)