High-frequency-stability laser at 1.5 {mu}m using Doppler-free molecular lines

An extended-cavity 1.5-μm semiconductor laser was frequency stabilized to saturated-absorption lines of acetylene. Its long-term frequency stability is of the order of 10−12, with a reproducibility of ±10 kHz. Using the lines of C2H2 or HCN, we could obtain such a high stability with the same laser at many wavelengths covering the 1.51 – 1.56-μm band.