Fiber-Based Acetylene-Stabilized Laser

We describe a fiber-based acetylene-stabilized laser system in which light is coupled to free space only to pass through the acetylene cell. The system is constructed using standard components used in telecommunication networks, making the approach straightforward to implement. The Doppler-free spectrum of acetylene can be detected, even without a lock-in amplifier using simple collinear pump-probe geometry, when the length of the optical path in the spectroscopy arrangement is dithered to cancel interference that is inevitably present in a fiber-based setup. The laser was stabilized to five different transitions of ¹³ C₂H₂ at the (nu₁ + nu₃) band using the third-harmonic technique, and the absolute frequencies were measured with an optical frequency comb generator. All the results are in good agreement with the values recommended by the International Committee for Weights and Measures (CIPM). The method for canceling the interference presented here can conceivably be generalized to other types of stabilized lasers as well.