本論文提出利用氦氖雷射打在光纖上的繞射圖形,藉由繞射圖形來檢測在二氧化碳雷射熔化法所製成的光纖品質,本系統改良傳統二氧化碳雷射法的製作,減少錐狀光纖製作完封包後,必須拿到光學顯微鏡下的步驟,本系統可以製作出其他光纖產品,近場掃描器的光纖探針等等。 在實驗中,由CCD Camera得到的繞射圖形,去校準光纖和氦氖雷射光點的相對位置,讓跟氦氖雷射共光路的二氧化碳雷射能有效率的打在光纖上,並且利用繞射圖形去判斷錐狀光纖的厚度。實驗中,其最好誤差值為-0.14(%/um),代表其系統是可以被應用的,而錐狀光纖的厚度為16um,其穿透率為30%。 In the thesis, we provide the improvement in fabricating tapered fiber by carbon dioxide laser melting method. We use the diffraction patterns formed by the fiber and He-Ne laser to investigate the quality of the taper fiber and calibrate the experiment system. The advantage of the system is to inspect the tapered fiber without packaging and reduce the cost. Moreover, we could utilize the system to produce probes for obtaining the super-resolution with the scanning near-field optical microscopy(SNOM). In the experiment, we demonstrate the tapered profile can be investigated by monitoring the far field diffraction patterns. Furthermore, the experimental results are in close agreement with the theoretical predictions and a tapered fiber with the waist of 16um was obtained.