Frequency locking of tunable Er:Yb microlasers to absorption lines of C132H2 in the 1540–1550 nm wavelength interval

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 of C132H2, 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 is 7×10−10 for integration times between 10−3 and 102 s.