Abstract. Lasers from three national metrological institutes (NMIs) have been measured following the protocol of the BIPM.L-K11 ongoing key comparison initiated by the Comité Consultative des Longueurs (CCL) 11th meeting in 2003. The absolute frequency of the f component of the R(127) 11-5 transition at 633 nm was measured for two of these lasers in their home institutes, AIST/NMIJ and UME, while the b₅ component of the R(106) 28-0 transition at 543 nm was measured on a standard from NIM at the BIPM. The results of these measurements are compiled in the present paper. The comparison reports, as communicated by each participant, are included as Appendices.

Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.

The final report has been peer-reviewed and approved for publication by the CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).