High performance multiplexer/demultiplexer devices fabricated from multiple fused fibre tapers

Conventional fused fibre WDM couplers offer very low loss 1.3/1.5 μm multiplexing/demultiplexing at potentially very low cost, but their applicability to many WDM system requirements is severely limited because of insufficient wavelength isolation and tightly confined operating channels at both 1300 and 1500 nm. Concatenation of fused fibre WDMs offer the potential for higher wavelength isolation over much wider operating channels, whilst retaining the attractive characteristics of fused devices such as low insertion loss and high directivity. The authors report on fully packaged duplexer components based on a `dual stage´ taper structure. Optical performance of a production batch of 50 devices is described, and their applicability of real system requirements discussed