Plastic optical amplifier using europium complex

Potential of polymer optical amplifier doped with europium complex has been analyzed for practical use in visible range. Europium tris(2-thenoyltrifluoroacetonate)-1,10-phenanthroline (Eu(TTA)(3)phen) was used as the amplification dopant and poly(methylmethacrylate) (PMMA) as matrix. Spectroscopic properties of the dopant such as metastable excited state lifetime, stimulated emission cross section, and stimulated absorption cross section were obtained using the photoluminescence spectroscopy, ultraviolet visible spectrophotometry and time-resolved spectroscopy. Lifetime of D-5(0) metastable state is 0.9 ms, which is longer than usual rare earth complex. Its emission cross section is comparable to erbium ions and absorption cross section is 4 orders of magnitude higher than bare rare earth ions. Optical amplifier was fabricated by the dip-coating method. The refractive index profile of the polymer optical amplifier was designed to manifest a single mode structure for the optimization of amplification performance. Amplification characteristics were simulated with respect to pump power, amplifier length, and number density of Eu(TTA)3phen. The simulations showed that optical gains are saturated above some maximum point. More than 30 dB optical gain can be achieved with 5 m long amplifier at 300 mW pump power.