藉著不同偏頻鎖相系統的方法，試著將兩台雷射的頻率差固定。成功將一台半導體雷射(僕雷射)與另一台頻率穩定的雷射(主雷射)做偏頻鎖相，產生高穩定的頻率差。本論文將介紹一個創新且簡單的偏頻鎖相系統，包括自製的相位偵測器與使用的 PI迴路。為了增加拍頻的功率，我們做出一台 tracking Oscillator，且為了增加 capture range ，以數位計數器維基礎做出修改版本。使用數位式與類比式相位偵測器的光學偏頻鎖頻系統，並且測量雷射拍頻的 3-dB 線寬。本論文中最好設計的拍頻的3-dB 線寬小於 1 mHz。 主雷射也是半導體雷射且擁有獨立的鎖頻系統，所以主雷射能提供穩定的參考頻率給僕雷射使用。最後，使用兩種不同的方法操作光學偏頻鎖相系統，測量銫原子的6S-6D的超精細躍遷譜線。藉由本論文中偏頻鎖相的技術，改變僕雷射頻率達到掃描銫原子譜線的目的。;We tried to make frequency difference of two lasers be stable by some offset locking. Using different approaches, we successfully offset locked the frequency of one diode laser (slave laser) against the other frequency-stabilized laser (master laser), resulting in a highly stable frequency difference. A novel and simple scheme of electronic offset locking includes phase detector, PI loop filter is reported. For boosting up the beat-note power, we also built up a tracing oscillator with which a freency counter-based device was installed for extending the capture range. We use both digital and analogic phase detector to demonstrate the optical offset locking. We used different approaches to measure 3-dB linewidth of beat-note. The best design can make the 3-dB linewidth of beat-note be smaller than 1 mHz. The master laser was a diode laser having an independent frequency locking system that could serve as a stable reference frequency of slave laser. To sum up, we can control optical offset locking to monitor cesium 6S1/2-6D2/3 hyperfine transitions by two approaches. The purpose is to scan cesium hyperfine transitions by changing the frequency of slave laser, using the developed offset locking technique in this thesis.