DYE-DOPED STEP-INDEX POLYMER OPTICAL-FIBER FOR BROAD-BAND OPTICAL AMPLIFICATION

We report the development of a novel and simple technique for fabricat ing polymer optical fibers of good optical quality for special device applications, This technique aims at polymer fibers doped with various functional organic materials. On the basis of the technique, step-ind ex polymer optical fibers doped with laser dyes have been fabricated, High-gain and high-efficiency optical amplification has been achieved in a Rhodamine B-doped polymer fiber with a low pump power of less 1 k W and pulse width 5 ns, Because a high dye concentration is used, the optimal wavelength range of optical amplification in this fiber is sig nificantly red-shifted toward the center of the communication window ( at 650 nm wavelength) of methyl methacrylate-based polymer optical fib er, The shift is from the originally 560 and 590 nm to presently 610 t o 640 mn, We also present experimental results that show good photosta bility of the Rhodamine B-doped polymer fiber, compared with those rec ently reported in the improved polymer material systems, From the expe rimental observation, we identified the thermally induced bleach of dy e molecules as the major contributing factor to the lifetime of our ma terial system.