Micro-integrated diode laser modules enabling mode-hop-free tuning and long-term frequency stabilization

We present a robust and compact hybrid micro-integrated ECDL-MOPA laser module developed for quantum technology applications. The laser module operates at a wavelength of 767 nm with a PM fiber-coupled output power of up to 360 mW. The module's dimensions and mass are 139×80×33mm³ and 800 g, respectively. We demonstrate a mode-hop-free frequency tuning range of 22 GHz using a control loop that derives its error signal from the spectroscopy of the frequency-selective element. This tuning range can be extended beyond 100 GHz by implementing a cascaded control loop. The free-running laser features a technical linewidth of approximately 165 kHz at 1 ms and a minimum overlapping Allan deviation of σ(τ=6s)=6⋅10^-10. A reduction of the frequency drift by up to one order of magnitude [i.e., from σ(τ=10⁵s)=10^-7 to σ(τ=10⁵s)=7⋅10^-9] was achieved at averaging times exceeding 500 s by stabilizing the laser to its internal volume holographic Bragg grating.