Slagmolen, BramBarton, MarkMow-Lowry, C.De Vine, GlennRabeling, DavidChow, JongRomann, AlbertZhao, ChunnongGray, MalcolmMcClelland, David2015-12-130001-7701http://hdl.handle.net/1885/73889In this paper we report on the alignment locking of an in vacuum 77 m long suspended mirror Fabry-Perot cavity. Lock was achieved by mode-matching a 500 mW Nd:YAG NPRO onto a pre-mode cleaner, the output of which was then mode-matched to the suspended cavity. The longitudinal locking was achieved by feeding back to the laser frequency actuator to follow the cavity resonance. Subsequent implementation of a hybrid auto-alignment system enhanced the stability of the circulating power inside the cavity. Preliminary results are presented.Keywords: Auto-alignment; Fabry-Perot; Interferometer; Laser frequency; Suspension200510.1007/s10714-005-0144-62015-12-11