PERSISTENT SPECTRAL HOLE-BURNING IN METAL-FREE TETRAPHENYLPORPHYRIN-DOPED POLYMETHYLMETHACRYLATE CORE FIBER

We report persistent spectral hole burning (PSHB) in metal-free tetrap henylporphyrin (TPP)-doped polymethylmethacrylate (PMMA) core fiber vi a the proton tautomerization of TPP. The TPP concentration was 1.25x10 (-4) M. The fiber structure of the PSHB material which we have develop ed made it possible to increase the number of guest molecules in the m aterial and to confine the excitation laser light over the whole lengt h of the material, both of which are important features for the achiev ement of optimum storage density in the PSHB storage scheme. We have c arried out PSHB experiments on three fiber PSHB materials whose diamet er and length range between 125-600 mu m and between 10-55 mm, respect ively. The largest hole formation yield of 4.3x10(-4) and a frequency multiplexity of about 1500 were obtained in a fiber PSHB sample (diame ter: 400 mu m, length: 52 mm) cladded with a UV curable adhesive.