Linewidth narrowing and wideband frequency modulation of a DBR laser

We present a scheme to phase-lock a 240 mW, 852 nm distributed Bragg reflector (DBR) laser to a fixed-frequency narrow-linewidth laser with a rapidly tunable frequency offset near 9 GHz. The phase-lock is accomplished by electronic feedback on the beatnote between the two lasers. The frequency offset can be swept 200 MHz in 300 <i>µ</i>s, limited by the feedback loop bandwidth, allowing for its use in complex cooling and state preparation schemes needed in atomic physics experiments. Additionally, we find that the phase-lock reduces the linewidth of the DBR laser below its natural linewidth of ∼400 kHz to ∼100 kHz.