Laser wavelength stabilization is achieved by locating a low selectivity reference filter in a reference path of a laser beam. The low selectivity reference filter, with a periodicity greater than the control filter, is used together with a lookup table for the reference filter to resolve the uncertainty associated with the multivalued control filter. After the wavelength uncertainty for the control filter is resolved, the laser beam is stabilized based on the response of the control filter, as if the reference filter was not present.