目前市售的光纖光柵節距多為通訊波長，可見波長的光纖光柵甚難取得，因此製造可見光範圍之光柵結構的技術有其必要性。在製造方面，雷射直寫光罩技術，受限於光波繞射極限，難以製作次波長光柵結構；而次波長光罩的製作成本高，不利系統研發。 本研究提出一種翻拍繞射光柵圖樣以製作光纖光柵之光罩的方法，該法可製作次波長光罩，且成本低、製程彈性高，可應用於製作不同節距之光罩。它是利用全像干涉微影技術(Holographic Interferometric Lithography)、黃光微影技術(Photolithography)，結合反應性離子蝕刻技術(Reactive Ion Etching)，研製具有繞射光柵圖案之光罩。 本論文現階段完成以全像干涉微影，搭配黃光微影製程將全像片上的繞射圖案轉移到光阻上，並對製程方面進行誤差分析。根據實驗結果顯示，以顯影時間25 s、曝光時間36 s的製程參數下，利用顯微鏡尺規量測，並成功地在光阻上製作出約為25um的繞射圖型結構。 Currently, most of the commercially available fiber gratings have wavelengths for communications. Fiber gratings for the visible range are difficult to obtain. It is necessary for manufacture of fiber gratings which are in visible range. For manufacture, the laser direct writing of fiber gratings is limited by the diffraction limit of optical waves so that it is difficult for the laser direct writing technique to make subwavelength structures. In addition, the cost of the subwavelength mask is so high that it is not a good choice to use the subwavelength mask for the research and development of a variety of systems. This study proposes a method to make photomasks and fiber gratings using reproducing the diffraction pattern. This method can make subwavelength fiber grating. This method is with low cost and high flexibility in fabrication. It can be applied to make fiber grating of various grating pitches. We adopted holographic interferometric lithography, photolithography, and reactive ion etching to fabricate the photomask with diffraction patterns. And the patterns on the photomask was transferred into the photosensitive fiber to make the fiber grating using an excimer laser system. At the present stage, this study has completed the use of holographic interference lithography and photolithography with the hologram on the diffraction pattern transferred to the resist. The resist we used is thick film photoresist resist AZ4620, developing time is 25 s, Exposure time is 36 s. Under these process parameters, we used microscope ruler to do the measurement, and successfully fabricated about 25 mm diffraction pattern structure on the resist.
