LIU Dan-dan1,2,3, WU Chang-jiang1,2,3, RUAN Jun1,2,3, LIU Jie1,3, ZHANG Shou-gang1,3

(1. National Time Service Center, Chinese Academy of Science, Xi’an 710600, China;

2. Graduate University of Chinese Academy of Science, Beijing 100039, China;

3. Key Laboratory of Time and Frequency Primary Standards, Chinese Academy of Sciences, Xi’an 710600, China) 

Abstract: In order to reduce the drift of frequency of the external cavity diode laser (ECDL) and improve the frequency stability of ECDL, a digital frequency stabilization method is presented in this paper. Based on the programming language LabwindowsCVI, the data acquisition card was employed to design a digital lock-in amplifier so that the frequency stabilization error signal can be obtained. Through controlling piezoelectric transducer (PZT) voltage by this error signal, the frequency of the ECDL can be locked to the Cs saturated absorption spectrum. The experiment results show that the high frequency stability of 8.7×10-11 for 20s integration time is achieved in this system. The method greatly reduces the device cost, meanwhile, it’s convenient to modify and upgrade the system. It also has characters of good transformation and friendly human-machine interface.

Key words: ECDL(extended cavity diode laser); digital frequency stabilization; data acquisition card; PZT(piezoelectric transducer)