A Distributed-Feedback Diode Laser Frequency Stabilized on Doppler-Free Cs $D_{1}$ Line

This paper describes a distributed-feedback laser diode system frequency stabilized by simple saturated absorption technique at 895 nm on the Cs D₁ line with a linewidth narrower than 1 MHz. This laser source was developed to be used in a compact cesium atomic clock based on coherent population trapping. The frequency stability of the laser system, evaluated by measuring the beat note of two similar laser systems and characterized by Allan deviation, is measured to be lower than 1 × 10^-11 for integration times of up to 2000 s, even achieving 4 × 10¹² at 200 s. This laser diode system, mounted in a mechanically stable cage system using easy-to-find commercially available components, remains in locked operation for several weeks without any problem.