A major problem of plastic optical fibers(POFs) is large transmission loss in comparison with silica fibers.After adopting a new optical fiber structure,hollow-core Bragg fiber with cobweb-structured cladding,which can suppress the absorption losses of constituent materials by a factor of about 104―106,the problem of POFs with large losses is solved ultimately.With the advantage of flexibility and easy bending,the POFs with this structure can guide light with low transmission loss for information and energy in the wavelength range of visible light to terahertz(THz) wave(0.4―1000 μm).This new generation of POFs will find many applications.
YU RongJin & ZHANG Bing College of Information Science and Engineering,Yanshan University,Qinhuangdao 066004,China
The noise in polymer optical amplifiers is mainly derived from the amplification of spontaneous emission (ASE). In this paper,the noise characteristic of dye-doped polymer optical fiber amplifiers is studied. The propagation equations of ASE power and the rate equations of dye molecular concentration are found based on the energy level transition of dye. The noise characteristic of optical fiber amplifiers is given by solving above equations numerically,and the relationship between noise figure and parameters of optical fiber amplifiers is investigated in detail. The result shows that the noise figure of dye-doped polymer optical fiber amplifiers will not exceed 5 dB.
A new type of Bragg fibers, i.e. hollow-core cobweb-structured optical fibers, which can be used to the low-loss transmis- sion from visible to near infrared region (0.65 μm-1.55 μm), terahertz wave (200 μm-480 μm) and circular-polariza- tion-maintaining single-mode transmission are investigated. Results show that the hollow-core cobweb-structured fibers have less loss than other hollow-core Bragg fibers. The fibers can be constituted by using the plastics or glasses with large absorption losses.
YU Rong-jin ZHANG Yong-qiang ZHANG Bing WANG Chao-ran WU Chang-qi
