| Summary: | 碩士 === 淡江大學 === 機械與機電工程學系碩士班 === 101 === 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.
|
|---|
