Diode laser wavelength standard based on 13C2H2 near-infrared spectroscopy at NIM

Diode Laser wavelength standards at the 1.5 μm optical telecommunication band have important application in the dense wavelength division multiplexing (DWDM). This need motivates the frequency stabilization by Doppler-free spectra of the molecule overtone, such as acetylene ¹³C₂H₂ or ¹²C₂H₂, HCN and ammoni ¹⁴NH₃. Especially, the P(16) line of ¹³C₂H₂ in the (ν1+ν3) band was adopted by the International Committee for Weights and Measures (CIPM) for practical realization of the definition of metre, which was given a uncertainty of 10 kHz with a relative uncertainty of 5×10-11. The recommended stabilized laser has elicited widespread interest in the national metrology institutes (NMIs). In this paper, we demonstrate an initially experimental result of the acetylene ¹³C₂H₂ stabilized laser using the Doppler-free spectra with one-way pump and probe configuration in the external acetylene cell. This stabilized near infrared laser employs a commercial external cavity tunable diode laser with the classic Littman-Metcalf configuration, and it could be applied in the optical fiber communication as a wavelength reference standard. A home-made 3f detection and servo system is taken to lock the external cavity tunable diode laser (ECDL) at the Doppler-free transition of the ¹³C₂H₂ P(16) line with one-way pump and probe configuration. The initial experiment results show that a standard deviation of the frequency fluctuation of 2.7 kHz and a relative stability of 4.2×10^-13 at 100 s are obtained, respectively. In the future, we will focus on the optimization of these systems, including disciplining the acousto-optic shift frequency to an atom clock and optimizing the parameters of the closed loop.