Improvement of all-optical switching performance based on azo dye-doped polymer film using two cross-linearly polarized pump beams

Abstract

We propose a method for improving the characteristics of all-optical switching based on azo dye-doped polymers. Using alternately two cross-linearly polarized beams (532nm, continuous light wave (CW)) to pump azo dye–ethyl red (ER) doped polymer methyl methacrylate (PMMA) film, the modulation depth of the all-optical switching reached 96% at the pump powers of 4.8mW and 1.6mW and the modulation frequency of 1000Hz. For comparison, we used respectively the single linearly polarized beam (4.8mW) and the alternately linear–circular polarized beams (4.8mW and 1.6mW) to pump the film at the modulation frequency of 1000Hz, the obtained modulation depths of the all-optical switching were 36% and 45.8%, respectively. Furthermore, the experimental measurement and analysis showed that the turn off speed of the all-optical switching could be obviously increased by use of our pump method.