Study of Broadband Fiber Source and Fiber-Optic Video Transmission

• Main Authors: Lin,Yun-Shi, 林耘世
• Other Authors: Chen,Yung-Kuang
• Format: Others
• Language: zh-TW
• Published: 1998
• Online Access: http://ndltd.ncl.edu.tw/handle/96885419519454220723

碩士 === 國立中山大學 === 海下技術研究所 === 86 === This thesis includes two parts: the broadband erbium-doped superfluorescent fiber source (SFS) for fiber optic gyroscope (FOG), and the fiber-optic video transmission technique of remotely operated vehicle (ROV). For the study of SFS for FOG, we investigate and compare the characteristics of erbium-doped SFS using different flattening techniques in double-pass forward (DPF) and double-pass backward (DPB) configurations. The intrinsic flattening is to optimize the erbium-doped fiber (EDF) length and pump power for an SFS to obtain high output power, wide line-width, and stable mean wavelength. The extrinsic flattening methods include addition of an appropriate length of the samarium-doped fiber (SDF) or by adding a short-period fiber Bragg grating (FBG) notch filter at the output port of the SFS. Experimental results show that both DPF and DPB SFS's have similar features in output power, line-width, and mean wavelength stability for each of the flattening methods. Although the DPF and DPB SFS's with the intrinsic flattening technique have a larger output power, they accompanied with large spectral power variation. The DPF and DPB SFS's with short-period FBG notch filter can achieve a wider line-width with excellent spectral flatness and better mean wavelength stability. To the best of our knowledge, both the FBG-flattened DPF and DPB SFS's are the most flat, broadband erbium-doped SFS's ever reported. On the contrary, both DPF and DPB SFS's using the SDF as a spectral flattener have no benefits in all characteristics. For the study of fiber-optic video transmission technique for ROV, we have investigated the feasibility of both wavelength division multiplexing (WDM) and sub-carrier multiplexing (SCM) techniques for ROV fiber-optic transmission system. Both techniques can reduce the required fiber counts, and thus decrease the outside diameter of the used optical fiber cable. Furthermore, simplify the rotary fiber-optic connector. In consequence, both techniques not only lower down the system cost of ROV, and make the operation of winches more easily, but also offer the expandability of fiber-optic communication system. For the SCM technique, the number of required optical transmitters and receivers can be reduced again as compared with the WDM one.