A compact laser system for the cold atom gravimeter

•We report a miniaturized and stabilized laser system for a gravimeter.•Just two DFB laser diodes are utilized for several laser frequencies.•We use a periodically poled lithium niobate(PPLN) crystal to obtain 780 nm laser.•The repumping and Raman lasers are obtained with a fiber electro-optic modulator.

With the rapid development of the technologies in the field of laser cooling atoms, a portable and stable laser system is urgently required for the wide applications based on the cold atoms. In this paper, we report a modular laser system for a gravimeter based on atom interferometry, which enable us to realize high-precision gravity measurements outside of laboratory. The system is based on two distributed feedback (DFB) laser diodes of 1560 nm, which are used as the master laser and the reference laser respectively. The frequency of the reference laser is locked on a rubidium transition, the master laser is frequency locked on the reference one by the method of beat locking. The master laser is power amplified firstly by the erbium-doped fiber amplifier (EDFA), and then frequency doubled by using a periodically poled lithium niobate (PPLN) crystal to obtain 1 W laser output at 780 nm. The repumping and Raman lasers are generated by adding an electro-optic modulation on the master laser, featuring extremely low phase noise. With this laser system, we obtain a cloud of Rb87 atoms with a temperature of 5 μKμKin a magneto-optical trapping. And a gravity resolution of 1.0×10−8g1.0×10−8g within 200 s integration time is reached.