Single supermode harmonically modelocked Ti:Er:LiNbO3 waveguide laser

Harmonically modelocked lasers are interesting sources for high bit rate optical transmitters. We have already demonstrated actively modelocked Ti:Er:LiNbO3 waveguide lasers with pulse repetition frequencies up to 10 GHz [1]. But, harmonically modelocked lasers usually emit more than one comb of longitudinal modes (so called supermode) causing high frequency noise. For fibre lasers with a large number of supermodes an intracavity Fabry-Perot filter with a high finesse (>50) has been successfully used to select one supermode [2,3]. In this contribution we report single supermode operation of a Ti:Er:LiNbO3 waveguide laser by coupling of the active laser cavity to a passive, low finesse (2.3) waveguide Fabry-Perot.