Fused couplers are used to split optical signals between two fibers, or to combine optical signals from two fibers into one fiber. They are constructed by fusing and tapering two fibers together. This method provides a simple, rugged, and compact method of splitting and combining optical signals. Typical excess losses are as low as 0.2dB, while splitting ratios are accurate to within ±5 percent at the design wavelength. The devices are bidirectional, and offer low backreflection. The technique is best suited to singlemode and multimode couplers.