A digital optical phase lock loop(OPLL)is implemented to synchronize the frequency and phase between two external cavity diode lasers(ECDL),generating Raman pulses for atom interferometry.The setup involves all-digital phase detection and a programmable digital proportional-integral-derivative(PID)loop in locking.The lock generates a narrow beat-note linewidth below 1 Hz and low phase-noise of 0.03 rad2 between the master and slave ECDLs.The lock proves to be stable and robust,and all the locking parameters can be set and optimized on a computer interface with convenience,making the lock adaptable to various setups of laser systems.
We experimentally demonstrate a simple modulation-free scheme for ofset locking the frequency of a laser using bufer gas-induced resonance.Our scheme excludes the limitation of low difraction efciency and laser input intensity when an acousto-optic modulator is applied to shift the laser frequency from the resonance.We show the stabilization of a strong 795-nm laser detuned up to 550 MHz from the87Rb 5S1/2F=2→5P1/2F’=2 transition.The locking range can be modifed by controlling the bufer gas pressure.A laser line width of 2 MHz is achieved over 10 min.
