Near infrared light amplification in dye-doped polymer waveguide

We have investigated near infrared amplified spontaneous emission (ASE) in dye-doped polymer waveguides under optical pumping. As a near infrared emitting dye, 2-[7-(1,3-dihydro-1,3,3-trimethyl-2H-indol-2-ylidene)-1,3,5-heptatrienyl]-1,3,3-trimethyl-3H-indolium iodide dispersed in poly(vinylpyrrolidone) was used. Dye-doped polymer waveguides were made by spin coating on glass substrates. According to gain and loss measurements at ASE peak wavelengths, the waveguides exhibited a very large net gain of 34.8 cm(-1) and a low loss of 8.4 cm(-1). This high gain performance was obtained at a dye concentration of 2.0 wt%, and was attributed to a large effective stimulated emission cross section of the doped dye. Furthermore, ASE wavelengths were varied in a range of 825-870 nm by doping concentrations because of self-absorption effects.