Characterization of commercially available vertical-cavity surface-emitting lasers tuned on Cs D-1 line at 894.6 nm for miniature atomic clocks

摘要

We report on the metrological characterization of novel commercially available 894.6 nm vertical-cavity surface-emitting lasers (VCSELs), dedicated to Cs D-1 line spectroscopy experiments. The thermal behavior of the VCSELs is reported, highlighting the existence of a minimum threshold current and maximum output power in the 55 degrees C-60 degrees C range. The laser relative intensity noise, measured to be -108 dB/Hz at 10 Hz Fourier frequency f for a laser power of 25 mu W, is reduced with increased power. The VCSELs frequency noise is 10(8) Hz(2)/Hz at f = 100 Hz. The spectral linewidth of the VCSELs is about 30 MHz. VCSELs injection current can be directly modulated at 4.596 GHz with microwave power in the range of -10 to +0 dBm to generate optical sidebands. A VCSEL was used in a microcell-based Cs atomic clock based on coherent population trapping. A preliminary clock short-term fractional frequency stability of 8 x 10(-11)tau(-1/2) up to about 100 s is reported, demonstrating the suitability of these VCSELs for miniature atomic clock applications. (C) 2016 Optical Society of America