We demonstrate frequency stabilization of widely tunable erbium–ytterbium microlasers in the wavelength interval between 1540 and 1550 nm by locking the oscillators to nine different absorption lines of13C2H2,spaced by approximately 150 GHz. Frequency stability is evaluated by measuring the two-sample Allan variance of the heterodyne beat-note signal between two identical lasers. The square root of the Allan variance is7×10−10for integration times between10−3and102 s.©1997 American Institute of Physics.