It has been twenty years since the first fused fiber optic coupler was made and remarkable progress has been achieved during this period on the production, performance, and reliability of these devices. Several million fused couplers have now been produced and placed into service. Applications have included test instrumentation, both outside plant and central office telephony applications, cable TV systems, sensors, optical amplifiers, DWDM systems, and submarine repeaters, to mention a few. To meet the increased production requirements, significant work has been done to make the process more flexible and thereby more amenable to automation and computerization. Modern fused coupler operations are highly automated and can make a large variety of products by simply changing a computer file. Similar improvements have also been made in high volume testing so that sophisticated tests of a number of parameters can be performed in a matter of minutes. As the volume and variety of the products have increased over the years, so has the performance. Improvements have been made in reducing excess loss, polarization effects, and wavelength dependence. In addition, higher port count devices (1 X 3, 1 X 4, etc.) have been developed. Numerous studies have been conducted over the years to determine the reliability of these devices. The introduction of glass-to-glass sealing techniques to isolate the fused region by bonding the fibers directly to the quartz substrate significantly improved the stability and long term reliability of these devices. The state-of-the-art production, performance, and reliability of fused coupler technology will be reviewed in this paper.