Size influence of nanoparticles on relative gain of polymer based optical waveguide amplifiers

Nanoparticles (NPs) doped polymer based optical waveguide amplifiers (OWAs) have been attracting much attention. As an important component of gain medium, the size of NPs has a significant influence on the relative gain of the OWAs. NPs with larger size have improved luminescence properties, but also increase the scattering loss in OWAs. Here, NPs with a broad size range from 10 nm to 100 nm were well synthesized and used in polymer based OWAs to study the influence of NP size variation on the relative gain. The luminescence intensity and lifetime of NPs increased with their size. However, the relative gain of OWAs doped with NPs of increasing size first increased and then decreased. When the NP size was 51 nm, the gain reached the maximum 12 dB/cm. These research results indicated that under our experimental conditions, when the NP size was 51 nm, the gain increase caused by the improvement of luminescence properties and the relative gain decrease caused by the scattering loss in OWAs reached a balance.