With the optical phase lock loop (OPLL) we made, we can achieve phase locking at frequency differences ranging from
0.5GHz to 7.5 GHz. This OPLL is fully applicable in atomic physics experiments, mostly in coherent lasers frequency
locking. Two kinds of modulation modes were brought to ensure the frequency range and precision: the fast feedback
current as the injection current and the slow feedback current to adjust the piezo-electric transducer. This device has been
put into an optical lattice platform to lock a laser used for cooling and trapping atoms. The beat signal has a -3dB band
width of 1Hz at 6.834GHz, corresponding to the hyperfine splitting of the ground state 87Rb atom.
We demonstrate a high-power pulse laser with extremely high pulse extinction ratio (ER). This laser module is designed
for the experiment of 217 km long distance photon-counting optical time-domain reflectometry (ν-OTDR) using an upconversion
single photon detector. The maximum peak power of laser pulse is over 24dBm with an extremely high pulse
extinction ratio of more than 100dB.