Asymmetric corrugated Long Period Fiber Grating Fabrication and their Optical Characterization

• Main Authors: Chen-You Chen, 陳禎祐
• Other Authors: Lon A Wang
• Format: Others
• Language: en_US
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/45989973305421094299

碩士 === 國立臺灣大學 === 光電工程學研究所 === 95 === The prior proposed corrugated fiber gratings overcome the limitation of conventional fabrication methods which is most cases require photosensitive fiber for making conventional long period fiber gratings. Besides, the corrugated structures enable the flexibility of tuning coupling strength and resonant conditions. However, making a corrugated structure on a fiber by thermal coating is not convenient and inefficient. Hence, a new lithography method was proposed in July 2006. To this thesis contains the previously proposed lithography method, but take advantage of V-grooves which are commonly used in the industry. We set a fiber in a V-groove and coat it with negative photoresist SU8 to protect the bottom of fiber. Then we make a periodic structure on the top of fiber. To finalize the fabrication of a asymmetric corrugated fiber grating. Besides, we use 3-layer etching method to improve the strength gratings and yield of fabrication of fiber. In addition to proving the tunable optical properties, The asymmetric corrugated fiber grating is found capable of coupling two wavelengths from core mode to cladding modes of two orthogonal polarization states when a mechanical force is applied. We use a polarization analyzer and an optical spectrum analyzer to characterize this phenomenon. Asymmetric corrugated fiber gratings made by employing the lithographic method exhibits unique optical characteristics. According to our analysis, it is believed that such fiber gratings may find may applications in optical fiber communication and fiber sensing.