During this thesis work, a frequency stabilization system for an External Littrow Cavity Diode Laser (ECDL) at 370 nm has been set up and tested. The goal of the frequency stabilization is to achieve a long term frequency stability of less than ±50 kHz within 8 hours, which will be used for the single Ce ion detection project in the quantum information group. The system design is centered around a Fabry-Pérot (FP) cavity which is composed of two mirrors optically contacted onto the ends of a cylindrical spacer made of Ultra-Low Expansion (ULE) glass. To first order, the cavity spacer has a zero thermal expansion coefficient around a certain temperature. The method for achieving the required frequency stability is to actively stabilize the ECDL output frequency through controlling both the ECDL driving current and the grating position by a piezoelectric actuator. Pound-Drever-Hall (PDH) locking technique [1] is used to lock the laser frequency onto one of the resonance lines of the stable FP cavity. To be able to get the desired performance each segment of the system has to be set up correctly. The work include aligning the laser beam polarization, coupling laser into a single mode polarization maintaining fiber, setting up the radio frequency resonance tank used for the Electro-Optic Modulator (EOM), putting together the vacuum chamber where the FP cavity sits inside, installing the cavity spacer into the vacuum chamber, aligning the laser beam to match the cavity modes and designing the electronic filter circuits etc. Finally, after eight months of hard work, this laser could be locked around 2 hours and gave a good start for the future work. However the locking performance has not been characterized due to the shortness of time. Considering the time plan for this thesis, the improvement for a longer-time locking is remained
