Heurs, M.Petersen, I. R.James, M. R.Huntington, Elanor Harriet2016-05-302016-05-300146-9592http://hdl.handle.net/1885/101756We report on the successful implementation of a new approach to locking the frequencies of an OPO-based squeezed-vacuum source and its driving laser. The technique allows the simultaneous measurement of the phase-shifts induced by a cavity, which may be used for the purposes of frequency-locking, as well as the simultaneous measurement of the sub-quantum-noise-limited (sub-QNL) phase quadrature output of the OPO. The homodyne locking technique is cheap, easy to implement and has the distinct advantage that subsequent homodyne measurements are automatically phase-locked. The homodyne locking technique is also unique in that it is a sub-QNL frequency discriminator.This work was supported by the Australian Research Council.3 pages© 2009 Optical Society of AmericaOPO-basedsqueezed-vacuumsourcelaserphase-shiftscavityfrequency-lockingsub-quantum-noise-limited (sub-QNL)homodyne2009-08-1510.1364/OL.34.002465