The project was until last year closely connected with two funded projects. “Certified reference materials for optical telecommunication wavelengths” funded by the EU Fifth Framework Programme and ”Optical communication wavelength references” funded by the Nordic Industrial Fund (NI).At SP evaluation of 13C2H2 and HCN as wavelength references for fiber-optic communication in the 1550 nm region was performed. Laser frequency stabilization was performed to one of the absorption peaks. The absorption peaks for 13C2H2 at 60 kPa and 13 kPa could be determined with an uncertainty of ± 1,53 pm and ± 0,42 pm, respectively. The uncertainty for the HCN lines were ± 4,7 pm. The frequency stabilization could be done with a maximum deviation of 2 pm using the 13C2H2 filled absorption cell at low pressure. Combined with other uncertainties, the relative stability in absolute wavelength was 2,5x10-6. The accuracy for the HCN molecule was limited by the large widths of the absorption peaks. Lowering the pressure could reduce the uncertainty. The limiting factor when using the 13C2H2 cells was the accuracy of the wavelength meter.At HUT work with the silicon etalon based reference was finalized and a journal paper was published . The work was also presented at a conference at PTB . Subsequently, a new approach was successfully demonstrated where the etalon reference was turned into a scanning wavelength meter monitoring the DWDM channel wavelengths and power levels .
 J. Tuominen, T. Niemi, and H. Ludvigsen, “Wavelength reference for optical communications based on a temperature-tunable silicon etalon”, Rev. Sci. Instrum. 74, 3620-3623 (2003).
 J. Tuominen, T. Niemi, and H. Ludvigsen, "Wavelength reference based on a silicon etalon, in proceedings of CREW Workshop & 182. PTB Seminar, in Braunschweig, Germany, 10-11 April 2003 (invited talk).
 M. Söderlund, J. Tuominen, T. Niemi, H. Ludvigsen, and M. Leppihalme, "Device concept for monitoring DWDM channels", in Proceedings of 29th European Conference on Optical Communication and 14th International Conference on Integrated Optics and Optical Fibre Communication (ECOC-IOOC’03), Rimini, Italy, paper We
3.2.2.Work on ethylene and methane, suitable candidates for the 1625 nm region, has been continued at DFM. DFM has finalized its highly accurate fiber laser reference standard locked to acetylene. The EU and Nordic projects were finalized and several presentations given.
 J. Henningsen, et al.,
A progress report was submitted in May 2004. A progress report has been available since 3 April 2003