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 <sup>87</sup>Rb 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.
Positioning parameters of four-wheel have significant effects on maneuverabilities, securities and energy saving abilities of automobiles. Aiming at this issue, the error factors of 3D four-wheel aligner, which exist in extracting image feature points, calibrating internal and exeternal parameters of cameras, calculating positional parameters and measuring target pose, are analyzed respectively based on the elaborations of structure and measurement principle of 3D four-wheel aligner, as well as toe-in and camber of four-wheel, kingpin inclination and caster, and other major positional parameters. After that, some technical solutions are proposed for reducing the above error factors, and on this basis, a new type of aligner is developed and marketed, it’s highly estimated among customers because the technical indicators meet requirements well.