A novel all-fibre tunable delay-line filter, with a simple structure based on two 3×3 fibre couplers and only one phase shifter is utilised for residual dispersion compensation in a 40 Gbit/s optical transmission system. In this experiment the dispersion tolerance of the receiver was successfully enhanced by 100 ps/nm.
Duthel, T., Jansen, S. L., Otto, M., Krummrich, P. M., & Schäffer, C. G. (2004). Tunable all-fibre delay line filter for residual dispersion compensation in 40 Gbit/s systems. Electronics Letters, 40(20), 1291-1292. https://doi.org/10.1049/el:20046217